bluuebunny/crossref_metadata_2025 huggingface dataset:
End Diaphragm Cracking of Box Girder Bridges due to Post-tensioning: Case Study
Authors: Maree Ahmed F. , Sanders David H.
Published: February 2021

Adequate dimensioning and detailing of box girders end diaphragm is critical for proper performance of post‐tensioned bridges. Current design methods have led to highly congested anchorage zones with construction issues and cracking problems. In order to study the performance of anchorage zones, box girders end diaphragms were instrumented in the field. Strain gauges were used in order to capture stresses in reinforcing bars and strains within the concrete elements. End diaphragm cracking was observed during post‐tensioning for one of the investigated bridges. These cracks were not noticed during regular inspection because they occurred on the inner face of the diaphragm inside the box section. Skew angle of the end diaphragm is a governing factor affecting cracks distribution. The paper will discuss reasons for the developed cracks and highlight design recommendations.
Dangerous synergies causing failures of historical structures
Authors: Drdácký Miloš , Cacciotti Riccardo , Slížková Zuzana
Published: February 2021

The safety and reliability of historical structures or structures generally are typically assessed under “ideal” load or environmental service conditions. However, natural events and human activity or intervention during the life of historical structures may generate synergic effects which decrease their safety and even cause serious defects or failures. This paper presents selected situations involving combined time dependent degradation and sudden impacts of natural or artificial loads or human activity, identifies problems involved in coupling incompatible materials with weather or climate effects and incompatible remedial or strengthening work on historical structures. It further deals with a common problem: inadequate design, harmful interventions, and inadequate protection or preservation treatments. Lessons learned in practice and basic recommendations for preventing catastrophic results are presented.
Experimental Research on Concentrated Load Transfer between Steel and Slender Reinforced Concrete Slabs by High Performance Saw- Tooth Connectors
Authors: Reimer Andreas , Schmid Volker , Al-Kroom Hussein
Published: February 2021

This paper presents the results of an experimental study on saw-tooth connectors. One main application of these connectors is in hybrid structures, where they connect steel struts or cables to slender concrete decks. In these connections huge and concentrated forces are transferred from steel into concrete. According to the structural system, these connections may occur in the middle or on the edge of the reinforced concrete deck. Depending on the location within the main structure the rc-deck itself is exposed to compression or tension. Therefore, four different build-in situations are being investigated on slender rc-slabs. The presented experiments assess the distribution of the shear force along the connector. A preliminary FE-analysis based on the elasticity theory is compared with the observed load-bearing behavior. The tests show that the loading of the rc-slab in compression or tension has a high impact on the load capacity. All the tests show brittle failure in the concrete. This issue is addressed and investigated during this study.
Climate impact optimization in concrete bridge construction
Authors: Ekström Daniel , Al-Ayish Nadia , Simonsson Peter , Rempling Rasmus
Published: February 2021

Estimates indicate that the total climate impact, from a lifecycle perspective, generated by Swedish construction processes reaches the same magnitude as emissions from all passenger cars in Sweden. A large part of the emissions from construction of roads and railways arise from production of steel and concrete used in bridges and other infrastructure structures. In this research, several cases of existing concrete bridges have been investigated. The case studies are in a very firm way analyzed, and then opportunities for reducing climate gas emissions are described and elaborated upon. Accordingly, design and dimensioning through the use of today’s technology and material selection are discussed. Without developing new ways to construct bridges, or comparing concrete with other materials, a useful guide on how to use technology and opportunities that are available for constructing climate smarter versions of standard bridges today is developed and described.
Climate Change: impact on snow load on structures and consequences on built environment
Authors: Croce Pietro , Formichi Paolo , Landi Filippo , Marsili Francesca
Published: February 2021

The effect of climate change could significantly affect, in the mid-term future, climatic actions and then the design of new structures as well as the reliability of existing ones, designed according the provisions of current or past codes. In this wok, a suitable procedure to derive snow loads on ground under non-stationary climate conditions is proposed, combining data provided by observational dataset and outputs of climate models. The analyses are performed for the Italian Mediterranean region and the results in terms of updated snow load maps are presented for movable 30 year time windows till 2100 according different greenhouse gas emission scenarios.
Prolife: Recalculating a steel railway bridge for determining strengthening measures, using an updated FEM model and site measurements.
Authors: van de Burg Mark , Steenbrink Arjen , Hesselink B. H. (Bert)
Published: February 2021

Under funding of the European Union’s Research Fund for Coal & Steel (Grant agreement no. RFSR-CT-2015-00025) the project ProLife (Prolonging lifetime of old steel and steel-concrete bridges) is undertaken to find innovative new ways how to extend the lifetime of existing bridges. Within ProLife many different strategies for strengthening old road and rail bridges are researched by different partners in the project. The goal of the project is to look at different strengthening measures and their influence on the remaining lifetime and life cycle costs of a bridge.

We will focus on rehabilitating a steel rail bridge with steel deck sections to strengthen the stringers and cross beams. These are the governing elements for the lifetime of regular bridges, since the main (truss) girders generally have a high enough capacity to cope with today’s loads. As a case study for this strengthening method the bridge over the river Waal in the Netherlands near Zaltbommel is used. This is an old (1932) truss girder bridge in a busy railway line with both passenger and freight trains. The methodology for strengthening this type of bridge is described using this case study.

In this paper we will give an insight in the way the FEM model was made. On-site measurements have been taken to verify and calibrate the model of which the results will be presented. It was found that for a detailed and accurate assessment of this kind of bridge on-site measurements are very important.
Monitoring of a bridge strengthened with post-installed coiled spring pins
Authors: Hällmark Robert , Collin Peter , Petersson Mats , Andersson Erik
Published: February 2021

Many existing bridges were not originally designed for the traffic loads and the number of load cycles which they now experience. In order to increase the load capacity of non-composite steel- concrete bridges, post installed shear connectors can be used. This paper describes a field monitoring of a steel-concrete bridge which have been strengthened with post-installed coiled spring pins as shear connectors. During the monitoring, the bridge was loaded with a 31 tonnes truck placed in specific positions while strains were measured in the steel main girders, together with the horizontal slip at the steel-concrete interface. The results indicate that the coiled spring pins prevent the slip and that they can be used for strengthening purpose. It is also observed that the friction in the steel-concrete interface can contribute quite a lot to the composite action, even though that effect cannot be accounted for in the design.
Assessment of the Structural Safety of the Schiphol Railway Tunnel
Authors: van der Sanden Pieter , Scholten Peter
Published: February 2021

The planned extension of the parking garage P1 in the centre of Schiphol Airport, in which a third storey would be build on top of the existing two, demanded a reassessment of the Schiphol Railway Tunnel underneath it. The assessment was based on the Eurocodes, on the Dutch standard NEN 8700 and on the Dutch guideline RBK. The major goal was to avoid or minimize strengthening measures. This is achieved by minimizing the calculated construction forces, by using 3D FEM plate models, by accurately determining the load from the parking garage and using the adjusted load factors for the safety level “Reconstruction”. Also the capacity of the construction elements was calculated as accurately as possible. Additional design shear capacity was gained using the benefits of the RBK, of the haunches and thickenings. The ULS was reviewed and strengthening measures were designed, mainly to locally increase the shear capacity.
Influences on Determining Structural Reliability
Authors: Hertle Robert , Brehm Eric
Published: February 2021

The influences to investigate when trying to assess the reliability of structures are manifold. Even if all the relevant stochastic parameters and data for establishing a typical reliability model are known, there are uncertainties to be considered which cannot be covered by probabilistic methods only. In a probabilistic analysis, the basic variables of a design problem, such as e.g. material strength or load effects, have to be modelled as random variables. From there, the failure probability of a mem- ber can be determined by use of methods of reliability analysis.

This relatively straightforward procedure reaches its limits when additional influences like the sim- plification and/or linearization of the design problem, the model-reality-antagonism, the paper- building site transformation or human error are to be considered. Especially the three latter are not tangible by stochastic methods only. As the nature of these issues is predominantly human, individ- ual competence or its opposite deprive a purely mathematical approach to achieving sufficient reli- ability.
Numerical Analysis of Stress Concentration Factors of CFRP- Strengthened Fillet Welded T-joints
Authors: Qitong Yu , Lewei Tong
Published: February 2021

A few past studies indicated that fatigue behaviour of welded joints in steel bridge strengthened using carbon fiber reinforced polymer (CFRP) sheet could be improved obviously. The authors in this paper try to verify the issue of how CFRP decreasing stress concentration at weld toe in fillet welded T-joints through numerical analysis. Stress concentration factors (SCFs) in fillet welded T- joints before and after CFRP strengthening were investigated respectively by 1560 finite element models using ABAQUS, with different parameters varying, such as fillet weld toe radius, CFRP reinforcing ratio and CFRP elastic modulus. It is concluded that all the parameters are important affecting the SCF of fillet welded T-joint, and using high elastic modulus CFRP can be the most efficient approach to decrease SCF. Parametric equations were proposed to calculate SCFs of fillet welded T-joints with and without CFRP strengthening.
Bridge Aesthetics: Two examples from India
Authors: Guliani RB Singh
Published: February 2021

On seeing aesthetically pleasing structures, we are touched if we are sensitive to beauty. Such structures do enrich us and elevate our soul. Aesthetic quality of design (beauty for an artist) in form and shape is defined & there are rules for achieving the beauty. However, simple application of rules may not be enough, an artistic talent and sense of beauty matters, which designer has been bestowed upon by HIM. When proportion, Order and symmetry are applied well, the object so produced has aesthetic value. Five important aspects form, character, detail, scale and proportion must be considered from first principles. [1]

Two Arch bridges have been recently completed / nearing completion in North East India, which will pave way for changing preferences for accepting aesthetics as preferred solution:

Sanjenthong Bridge at Imphal: 4 lane Bow String Arch bridge, span 56m

Bridge over river Wahrew in Meghalaya: Steel latticed arch bridge, span 150m.

Principles devised by Dr Fritz Leonhardt, which are very effective in objectively assessing the aesthetical appeal of a bridge are used.

Sound Engineering is necessary for good design of lasting value, but may not lead to beauty in itself. Beyond rational thinking of an Engineer, objective must be there to create beauty. Artist, when engaged, should work for purpose of the structure rather styling it! Beauty of design will reach lasting value only if the bridge achieves its purpose.
Distributed Sensing to Assess the Impact of Support Conditions on Slab Behaviour
Authors: Nurmi Sara , Mauti Gabriella , Hoult Neil A.
Published: February 2021

Support conditions, specifically axial restraint, have a significant impact on the behaviour and load carrying capacity of flexural members such as slabs. However, in conventional design these beneficial effects are ignored since they cannot be accurately quantified. In the current work two reinforced concrete one-way slab specimens were tested in three point bending with and without axial restraint. Each specimen was instrumented with distributed fibre optic strain sensors to assess the impact of the support conditions on the internal strain behaviour. The load deflection data for the two specimens is used to assess the impact of the support conditions on stiffness and capacity. The internal strain data is used to evaluate the degree of support restraint and the impact on the internal stress state for each specimen.
Distributed fibre optic sensor system to measure the progressive axial shortening of a high-rise building during construction
Authors: de Battista Nicholas , Harvey Ross , Cheal Nick
Published: February 2021

A novel approach is being used to measure the progressive axial shortening of key structural elements of Principal Tower, a 50-storey reinforced concrete building in London, as it is being built. Distributed fibre optic sensor (DFOS) cables are embedded inside two columns and two core walls, from which the axial strain profile can be measured along the whole height of the constructed elements. Measurements are being taken regularly throughout the construction process, making it possible to observe the change in strain, and thus the axial shortening, within these elements, at any stage of the construction. This helps the design engineers and contractor verify the predicted differential shortening and adjust the column height presets if necessary. The purpose of this paper is to describe the monitoring system and to present initial data recorded from the first five levels of the building.
The Existing Champlain Bridge – Assessment Using Refined Analyses
Authors: Mitchell Denis , Cook William D. , Massicotte Bruno , Yildiz Emre
Published: February 2021

In order to evaluate the performance of the post-tensioned I-girders and diaphragms in the existing Champlain Bridge, a combination of 3D linear and 2D non-linear finite element analyses were carried out. After 55 years in service, many girders are experiencing deterioration. The results from the 3D analyses enabled the determination of the loads applied to individual girders and diaphragms for the non-linear analyses. The 3D analyses also enabled the determination of the redistribution of forces in the structure due to different degrees of corrosion of the tendons in the girders. The 2D non-linear finite element analyses captured the responses of the girders and diaphragms and enabled an assessment of the performance under service and factored loads. The degrees of corrosion of the tendons and the stirrups were estimated from inspection results. The effects of different strengthening measures were also assessed using this approach.
Extending Building Façade Performance Requirements for Blast: Hazard and Injury Assessment Investigations
Authors: Marchand Kirk A. , Davis Carrie E. , Conrath Edward J. , Hadjioannou Michalis , Earl William R.
Published: February 2021

Existing criteria for protection of occupants in government owned and/or occupied facilities in the US is largely based on estimates of damage limits for conventional façade structures and materials such as concrete, brick and concrete masonry, and glass. These damage limits are commonly based on extent of damage as a function of lateral deformation or ductility and the extent to which that deformation requires subsequent repairs or allows re-use. This approach works well for new construction where modest strength and mass increases can provide sufficient capacity at minimal cost so as to not exceed deformation limits. For existing buildings and historic facades, the approach can be onerous and inefficient, since retrofits to large sections of the façade may be required.

This paper describes initial efforts to define blast performance requirements for existing buildings in terms of occupant hazard based on injury potential rather than on deformation limits. Existing injury data and simplified façade failure and debris kinematics and analytics are used to relate applied blast load to actual occupant hazards. The approach provides information to building owners and stake holders that can provide much more efficient and cost effective extents for façade retrofits. The retrofits required are also more efficiently localized to lower levels and higher threat locations near the building.
The Ordsall Chord, Manchester, UK – digital delivery of design
Authors: Duguid Brian , Hyde Jason , Pullan Howard
Published: February 2021

The Ordsall Chord is a new railway link which for the first time connects all five of Manchester’s city centre railway stations. It involves extensive and varied structures supporting nearly 700 m of track, many of which are highly complex geometrically to satisfy architectural requirements.

The design across all engineering disciplines has been undertaken using extensive state-of-the-art Building Information Modelling (BIM). Federated 3d models produced by all disciplines are integrated in a common data environment, compliant with UK government BIM Level 2 requirements.

The level of detail developed for the civil and structural engineering design is unprecedented for a transport infrastructure project in the north of England, with modelling in many cases down to the level of individual reinforcement bars. Software interoperability issues have been encountered and resolved.

Early involvement of both the main contractor and steel fabrication subcontractor has allowed conventional roles and processes to be challenged. The design models and drawings have been produced on the designer’s behalf by the steelwork subcontractor, although the structural designer still owns these deliverables. For one structure, drawings were dispensed with entirely and this structure was built directly from the 3d model, prepared in collaboration between fabricator and designer.

Adoption of these methodologies has supported successful delivery of structures with challenging geometric interfaces between steelwork, concrete, and existing brickwork arches. This has reduced programme and safety risks during fabrication and installation, and will provide a platform for enhanced management of the structural assets in the future.
Derailment of an overhead gantry for the erection of precast concrete girders
Authors: Hingorani Ramón , Tanner Peter
Published: February 2021

This article explores the reasons for the derailment of an overhead gantry during construction of a precast concrete girder viaduct. Inasmuch as the accident occurred on the last out of 13 spans on one of two nominally identical parallel bridges in which no prior anomalies had been detected, a detailed forensic investigation was in order. The parallels among numerical calculations, experimental findings, eyewitness accounts and reconstruction of the accident sequence lent support to the identification of the most likely hazard scenario. The underlying causes were associated with less than optimal interfacing and data exchange among the actors involved in viaduct construction. The study showed that in addition to efficient quality assurance strategies, clearly defining each actor’s tasks and responsibilities is of cardinal importance in preventing construction worksite accidents.
Retrofit of Concrete Members with CFRP Rod Panels (CRP 195)
Authors: Jawdhari Akram , Harik Issam
Published: February 2021

Recently, a novel technique comprising small diameter carbon FRP (CFRP) rods arranged in a panel form (known as CRPs) has been developed and deployed. One of the technique’s advantages is the segmental construction, achieved by using short-length rod panels made continuous via an overlap (or finger joint). In this study, four-point bending tests were performed to assess the effectiveness of the rod panel system in strengthening RC beams. The rod panel investigated here is called CRP 195 and is fabricated from CFRP rods with diameter of 4 mm (0.16 in.) and spacing between rods of

9.4 mm (0.4 in.). The tests include: a control beam; and three beams strengthened with one of the following reinforcements: continuous CRP 195; overlapped CRP 195; and overlapped CRP 195 anchored at ends with U-shaped FRP fabrics. Results showed that the capacity increase of strengthened specimens as compared to the control beam is as follows: 104% for the continuous CRP 195; 95% for the overlapped CRP 195; and 195% for the overlapped CRP 195 with end anchorage.
Northeast Anthony Henday Drive / Yellowhead Trail Interchange Flyover Ramp Bridges
Authors: Lewis Myles
Published: February 2021

The three level system interchange connecting Northeast Anthony Henday Drive and Yellowhead Trail implement two flyover ramp bridges. To improve construction efficiencies, the contractor team sought implementation of continuous chorded (kinked) girders rather than conventionally curved girders to accommodate the curved ramp geometry. The multi-span structures comprised of kinked straight I-girders, forming horizontally curved alignments, imposed unique design challenges that were not explicitly addressed within the Canadian bridge code. This paper showcases the two flyover bridges; a 315 m long five span bridge with a radius of 340 m and a 415 m long six span bridge with a 347 m radius. Design challenges and considerations encountered during the design and construction are presented.
Experience of duplex stainless steels as construction materials in bridges: Results of seven inspections
Authors: Mameng Sukanya Häg , Tigerstrand Claes , Larsson Tobias , Gedge Grahamn , McCray Jonathan
Published: February 2021

Duplex stainless steel (DSS) usage in bridge construction has increased significantly in the last twenty years because of the material’s exceptional mechanical properties, good corrosion resistance, negligible need of maintenance and thereby low life cycle costs. Three suitable DSS grades used in bridge structures are EN 1.4462, 1.4362 and 1.4162. It is important to choose a DSS grade which is appropriate for the intended service environment, not least because the price of the material generally increases with the corrosion resistance. This work presents the results from various bridge inspections where DSS has been used for the main structure in environments which were retrospectively classified in accordance with EN 1993-1-4 Annex A. The results illustrate successful application of DSS structures and could also be used to provide data for future design standard revision, for example EN 1993-1-4, Annex A, relating to material selection.
Pendulum-type bearings / seismic isolators – solutions and case studies
Authors: Spuler Thomas , Brüninghold Max , Mendez-Galindo Carlos
Published: February 2021

Pendulum-type bearings, or curved surface sliders, have much to offer in bridge construction, particularly as a means of seismic isolation in earthquake-prone areas, but also, for example, in supporting the decks of bridges that are designed for heavy railway loading. A number of variations of this type of bearing have been developed – with non-spherical sliding surfaces, for example, or multiple sliding / rotation interfaces. The features and benefits of these different types are described, with reference to illustrative case studies.
Effectiveness of FRCM System in Strengthening Reinforced Masonry Walls Subjected to Cyclic Loading
Authors: Al-Jaberi Zuhair , Myers John J. , ElGawady Mohamed
Published: February 2021

Much of the research on the strengthening of masonry structures has focused on strengthening ofunreinforcedmasonry structures; as a result, most strengthening design guidelines are limited to this type of structural strengthening. In addition, only a limited experimental database of reinforced masonry structures with strengthening is available. The main purpose of this research is to study the behavior of fully grouted reinforced masonry walls strengthened with Fiber Reinforced Cementitious Matrix (FRCM) system under out-of-plane action. Seven reinforced masonry walls strengthened in flexure using (FRCM) were built as a part of this study. Two reinforced walls constructed in running and stack bond pattern were investigated as control specimens and the other specimens were strengthened using different types of fibers. FRCM strengthening composite materials consisted of one or two plies of fabric embedded in cementitious mortar. The test results indicated that the FRCM system is a very effective technique for upgrading flexural capacity of masonry walls and improve the behavior of stack wall.‌‌
Shaking Table Test Using Scaled Model of Reinforced Concrete Column Considering Time Variation from Similitude Conditions
Authors: Park Jamin , Cho Jae-Yeol
Published: February 2021

In a scaled model test of RC column, mortar and micro concrete are broadly used as model concrete whose material characteristics are different to that of ordinary concrete for prototype. In this case strain ratio which denotes scale factor of strain becomes not unity, and this is so called strain distortion. Furthermore, from nonlinear material characteristics of concrete, the strain ratio becomes not constant but variable during model tests.

In similitude law, strain ratio is related to scale factor of time. It indicates that time of input ground acceleration used for model tests should be different to that used for prototype tests when variation of strain ratio is occurred. However many researches on dynamic test using RC model have not considered this similitude requirements and this can cause errors in predictions for responses of prototype.

In this study, shaking table tests using RC scaled model considering the strain distortion and the variation of strain ratio were conducted. Predicting the variation of strain ratio by a developed analytical procedure, input ground acceleration of model was modified by following the similitude requirements. Test results shows that accuracy of prediction for response of prototype is significantly improved when using the modified input ground acceleration.
Durable design of a 42m full FRP footbridge for Bergen, Norway.
Authors: Tromp Leisbeth , Van Ijselmuijden Kees , Boeters Ton , Persson Stian
Published: February 2021

A tender design was prepared for a bridge at Paradis, Bergen, Norway. It is a full Fiber Reinforced Polymer (FRP) structure. The material and detailing have been optimised for the application in the Norwegian wet and cold climate. With its free span of 42m, this bridge is one of the longest spans for bridges in full FRP worldwide. In close cooperation with the Client, Statens vegvesen, a design for a pedestrian bridge was prepared by the team consisting of architects and engineers of RoyalHaskoningDHV. Statens vegvesen requires a low maintenance solution to minimise life cycle costs and hindrance for traffic on road and rail. The choice for FRP was made to prevent durability issues due to thermal fatigue and salting in winter times. This paper presents the interaction of design, material and manufacturing process. It describes the results of the structural analysis and highlights the principle of the solutions for reliable and easy to assemble connections.
Member Stiffness for Frame Analysis of GFRP Reinforced Concrete Structures
Authors: Bischoff Peter H.
Published: February 2021

The ACI 318 Building Code provides flexural EI stiffness values for elastic analysis of steel reinforced concrete buildings, with a moment of inertia 𝐼𝐼 equal to 0.7𝐼𝐼𝑔𝑔 for columns, 0.35𝐼𝐼𝑔𝑔 for beams, and 0.25𝐼𝐼𝑔𝑔 for flat slabs at factored loads (1.0𝐼𝐼𝑔𝑔 for columns, 0.5𝐼𝐼𝑔𝑔 for beams, and 0. 35𝐼𝐼𝑔𝑔 for flat slabs at service loads). This paper recommends design values of the moment of inertia for analysis of glass fibre reinforced polymer (GFRP) reinforced concrete members based on current ACI 440 design requirements. Results at the factored load level suggest using a value of 𝐼𝐼 equal to 0.4𝐼𝐼𝑔𝑔 for columns and 0.15𝐼𝐼𝑔𝑔 for beams and slabs. At the service load level, recommended values are increased by 50 percent to give 0. 6𝐼𝐼𝑔𝑔 for columns and 0.225𝐼𝐼𝑔𝑔 for beams and slabs.
Methodology for selection of production method in an early stage
Authors: Karlsson Mats , Rempling Rasmus , Gylltoft Kent , Plos Mario
Published: February 2021

The design of buildings and load carrying structures in early stages is a challenging task for a number of reasons; scant information generally exists and several different requirements involving building structures should be managed, including technical, environmental and financial requirements. However, this phase of the design process is important and will fundamentally influence the following construction phase, as well as the entire life of building structures. It is particularly important that the construction phase is properly considered already in the design phase and that the production method selected is suitable for the design of building structures. The purpose of this research has been to improve the design process in the conceptual phase. The findings will highlight the benefits of design for production in bridge engineering. The aim has been to identify examples of practices and work methodologies that are of good caliber in the Swedish bridge construction sector. Early findings show that there exists a divergence between research findings and current practices. The research community has presented several participatory methodologies for the design process, such as Early Contractor Involvement (ECI) and Integrated Project Delivery (IPD) for the potential of improving effectiveness in bridge engineering. However, studies of current practices in industry show that these methodologies are difficult to implement and that there are hidden consequences. The processes developed should manage several requirements simultaneously, including technical, environmental, health and safety, and financial. Competencies involved include Structural Engineering, Architecture and Production Management, in addition to expertise in health and safety, materials science, environmental impact and procurement. Further, the intention is for the processes to deal with verification methods for the proposed conceptual solutions and risk analyses based on quality assurance. Both new and existing building structures should be considered.
Development of a Two-way Column-supported Flat Plate in Cross Laminated Timber
Authors: Schneider Brett H. , Forrest Aaron , Vobis Yasmin , Croteau David , Oberholzer Mathias
Published: February 2021

Chicago Horizon is a pavilion for the 2015 Chicago Architecture Biennial that is composed of a flat roof made entirely out of Cross-Laminated Timber (CLT). The application of two-way column- supported flat plate in timber (for both the gravity system and as part of the lateral-load-resisting system) is possibly unique to this structure. This paper details the analysis, design, detailing and fabrication of the structure relating each to the translation of the flat plate structural type to CLT. This paper highlights: the comparison between two conceptual options for flat plate realization; the application of fasteners at 45 degrees to provide shear reinforcement of CLT locally; and the use of the laminated timber columns moment connected to the CLT flat plate to form the pavilion’s lateral- load-resisting. This unique application was developed through a close collaboration between the authors (architects, engineers and fabricators) and is the development of a new structural type in mass timber.
Fatigue Damage Assessment of Stay Cables for Light Rail Transit Bridges
Authors: Coughlin Reid , Jiang Jianping
Published: February 2021

The use of cable stayed structures for long span bridges gained popularity in the late 20th century with the development of advanced construction materials and equipment, and advancement of sophisticated structural design and modelling capabilities. There are many light rail transit (LRT) cable-stayed bridges in use today. Due to the repetitive cycling loading from passage of similar trains, the potential risk of fatigue-induced damage to stay cables is significantly higher for LRT bridges than roadway bridges. As LRT bridges carry heavier trains and provide increased levels of service, the fatigue induced damage to stay cables and its impact on the remaining service life has been frequently raised by transit authorities. This paper presents a recent study completed on assessing fatigue induced damage to stay cable for a LRT bridge including numerical analysis, processing of historic and future train data, and field investigation of the bridge’s response.
The New Champlain Bridge – Performance and Design Criteria
Authors: Nader Marwan , Sanjines Alex , Choi Carol , Duxbury James
Published: February 2021

The New Champlain Bridge, designated as a life-line structure, is one of the highest profile infrastructure projects in North America due to its critical economic importance, the premature deterioration of the existing structure, and its visibility throughout the metropolitan area.

The new bridge is comprised of three bridges: a 529 m Signature Span comprised of a asymmetric Cable-Stayed Bridge with a main span of 240 m; a 762 m East Approach with a maximum span of 109 m; and 2044 m West Approach with a typical span of 80.4 m.

This paper discusses the performance and design criteria used in the design of the bridge, including those defined in the Project Agreement (PA) and the various site-specific investigations and hazard assessments.
Innovative Means and Methods for the New Champlain Bridge
Authors: Osborne Gonzalo , Rogerson Jeff , Guitard Fréderic , Mylocopos André
Published: February 2021

Signature on the Saint Lawrence Construction (SSLC), a consortium comprised of SNC-Lavalin inc., Flatiron Constructors Canada, Dragados USA and EBC, is mandated to build the New Champlain Bridge Corridor Project (NCBCP). Significant challenges include:

Construction schedule: The Bridge must be in service by December 2018.

Navigation restrictions: The Seaway traffic must be maintained during the main span’s construction.

This paper discusses the following innovative construction methods used for the New Champlain Bridge (NCB):

A custom-built gantry to install the precast footings/pier starters in the river;

The delivery system for the segments to the tip of the deck in the main span.

These erection systems were developed and selected to suit the specific challenges of the project, including speed of construction, maintenance of shipping and environmental protection areas.
Design and Construction of a Lagoon Bank Protection Structure with Precast Counterfort Wall System
Authors: Tan Geem Eng , Ong Tai Boon , Choong Kok Keong , Ong Chong Yong
Published: February 2021

A precast counterfort wall system developed for bank protection structure for a large lagoon and waterfront development in Nusajaya, in the state of Johor of Malaysia is presented. The 5.25m high vertical earth retaining walls with 4.05m submerged depth below sea water level and 4500m total length of irregular layout were to be completed within 12 months together with massive cut- and-fill earthworks. Conventional in-situ reinforced concrete construction has been ruled out due to time and cost factors, and uncertainty in finished quality. A structurally efficient precast section with sloping “Tee” stiffener integrated with wall and base in manageable size was conceptualised, designed and developed with special considerations to aspect of construction. The economically viable solution adopted was a retaining wall system made of precast counterfort wall unit, strengthened with precast tie-slab and in-situ toe-beam, and finished with in-situ capping beam. Some 82.7% of concreting works were precast off-site, enabling site clearing and preparation works to commence simultaneously. The challenges of product design, manufacturing and installation are highlighted.
Seismic isolation of La Meynard Hospital, Martinique
Authors: Cynober Charles , Vezin Jean-Marc
Published: February 2021

The new technical support center of La Meynard hospital is meant to be operational just after an earthquake. This lead to design an isolation system. Rubber bearings have been used together with viscous dampers, which enable to decrease the building acceleration from 12.6 m/s² down to 1.6 m/s². A non-linear time history analysis of a simplified model was used to pre-design the isolation and damping system. The detailed calculations, was done by the company NECS on a 3D finite elements model of the structure, which took into account isolators and dampers. This analysis enabled to improve the design, particularly concerning the dampers orientation. The devices were manufactured by Freyssinet and tested according to NF EN 15129 standard. The installation of the devices was performed at the beginning of the construction. Works lasted forty four months from March 2013 to November 2016.
US Olympic Museum
Authors: Potapova Lana , Carter Matt , Jensen Merica , Nielsen Any , Krager Kathleen , Phipps Ryan
Published: February 2021

The US Olympic Museum (USOM) Footbridge is a 245ft clear spanning footbridge over Union Pacific Rail Road. This bridge is situated at the foothills of Rocky Mountains in Colorado Springs, Colorado. The dramatic and unique Rip-Curl concept will enhance the landscape between future US Olympic Museum and America the Beautiful Park. The footbridge is designed in collaboration with AMD architects, DS+R architects, UP Rail Road and City of Colorado Springs.

The Rip Curl superstructure is a sweeping asymmetrical steel shell morphed from an arched 70 ksi steel top chord and a “stressed skin” web. The concept is designed to both integrate with the aesthetic vision for the US Olympic Museum and to minimize impact on busy rail operations during construction as well as reduce maintenance for the client. This paper describes the rigorous analysis and design behind this unique concept
Adding value through innovation in structural design: 2 – Innovative design of timber structures
Authors: Fast Paul
Published: February 2021

This short paper will focus on opportunities for innovative thinking in the creation of hybrid structures and how this innovation can add value – the theme of an open forum discussion seminar led by the Institution of Structural Engineers at the 2017 IABSE Symposium in Vancouver.

During the past century, steel and concrete have dominated as primary building materials for structural designers. Timber has – for many years – remained the neglected child; when it is used, its design is often relegated to timber manufacturing firms. This paper and subsequent presentation will address emerging factors in our industry that will increase opportunities for structural designers to sensibly introduce wood into their design repertoires, often in combination with steel and concrete, to create functionally and cost‐efficient structures that address the sustainability concerns of our day. Drawing on the collective wisdom of engineers who were ‘out of the box’ thinkers, it will also provide some foundational thought and stimulating discussion that assesses what it takes to become a fresh thinking engineer who considers all material combinations when designing structures.
Adding value through innovation in structural design: 3 – Creativity and innovation in building structures
Authors: Franck Lee
Published: February 2021

This paper is part of a series on the subject of adding value through innovation in structural design

– the theme of an open forum discussion seminar organised at the conference by the Institution of Structural Engineers.

It explores different routes which can lead to creativity and innovation in building structures. It also identifies key drivers and enablers of innovation and the wider design philosophy that is needed for it to flourish.
Innovative solutions for Bridge strengthening (widening and compliance to new codes) by modification of initial static scheme
Authors: Buchin-Roulie Vanessa , Kaczkowski Nicolas , de Courcelles Charles , Toth Miklos
Published: February 2021

Strengthening of bridges for compliance to new codes is nowadays quite usual, but some innovative solutions have to be found for economic reasons, when loads increase due to widening or seismic actions is huge and has a strong impact on foundations, or when other parameters such as vibrations need to be considered. Freyssinet’s solution on 2 projects, Binh Trieu Bridge in Vietnam and Ayala Bridge in Philippines is a complete change of static scheme: isostatic bridges are transformed into hyperstatic bridges or portal frame mixing together: new elements of concrete, additional prestressing, dampers, change of bearing conditions, with only one goal “reduction of global cost of strengthening solution.”
Fatigue Performance of a Precast Hybrid FRP-Reinforced Bridge Truss Girder System
Authors: El-Badry Mamdouh , Moravvej Mohammad , Joulani Parham
Published: February 2021

The fatigue behaviour of a novel precast hybrid bridge truss girder system is experimentally investigated. The girders consist of pretensioned top and bottom concrete chords connected by vertical and diagonal truss members made of concrete-filled fibre reinforced polymer (FRP) tubes. The truss members are connected to the top and bottom chords by means of long double-headed glass FRP (GFRP) bars. The chords are also reinforced with GFRP longitudinal bars and transverse stirrups. Six large-scale truss girders were fabricated and tested. All girders had identical cross-section dimensions with 1.32 m overall depth. Three of the girders were 2.83 m in length. The remaining three were

9.82 m long. One short and one long girder were tested under static loading up to failure. The remaining four girders were tested under cyclic fatigue loading of different levels and amplitudes. The tests showed excellent performance of the truss girders in terms of strength, stiffness, and fatigue life.
Columbia River Skywalk – Turning a Need into a Landmark
Authors: Gubbins Julie , Cap Roman , Alca Nedim
Published: February 2021

The Columbia River Skywalk, designed by COWI North America Ltd., is a new pedestrian / pipeline suspension bridge located in the City of Trail, BC, Canada. The bridge carries pedestrians in addition to two utility pipelines. The bridge spans the Columbia River with a total length of 280 m (main span of 225 m). Aesthetics and cost were key objectives and were achieved through early communication with contractors, use of different construction materials, close work with the pipe designers, and attention to detail. This paper describes the design details developed to increase constructability and to address aesthetics in addition to discussion of the alternate materials, pipe design approach, and features included to address wind and pedestrian loading. In addition, the paper describes how the project evolved from a basic utilitarian pipe crossing to one that provides significant social value to the City of Trail, and COWI's role in it.
A manufacturing process approach to construction: design and application of a composite system for modular buildings
Authors: Chaillan Gilles , Condon Patrick , Poirriez Catherine , Wu Sophie
Published: February 2021

Singapore Authorities are actively promoting construction industrialisation through the Prefabricated Prefinished Volumetric Construction (PPVC) method so as to reduce the city-state’s dependence on foreign labour. This paper features the technical options of the modular system that were engineered for the Ministry of Health Holdings’ Woodlands Crescent Nursing Home in Singapore. This system, developed in response to constraints imposed by the design disciplines, factory fabrication, transport, and site erection can be used on a wide array of building types, including high rise hotels and apartments. The paper presents the choices taken in defining the modular system; unconventional structure design, especially on the influence of transfer floors and module layout; fire proofing and corrosion protection; the methodology used for the module construction as well as erection; and finally, the further development of this system.
Quality Control Plans for Girder and Frame Bridges
Authors: Linneberg Poul , Mašović Snežana , Hajdin Rade
Published: February 2021

Infrastructure managers works every day according to some kind of Quality Control Plan (QCP) in order to ensure a desired quality with minimum traffic interruption balancing cost, risks (implicit or explicit) and performance. These QCPs varies significantly among European countries, which urges the establishment of a common European guideline. COST TU1406 Working Group 3 has the aim of providing a detailed explanation of the steps towards the establishment of a QCP. The approach is generic and evaluates performance values with due attention to: 1) Structure and its constitutive element incl. background material such as birth certificates, 2) Time-dependent Performance Indicators (PI) from observations (e.g. spalling) with due reference to the underlying deterioration processes (e.g. alkali-silica reaction) and 3) Related Key Performance Indicators (KPI) based on the Dutch risk-driven maintenance concept RAMSSHE€P [1]. This paper outlines QCP's for concrete girder and frame bridges.
Strengthened Unreinforced Masonry (URM) structures with Ultra High Performance Fibre Reinforced (UHPFRC) layers under axial in-plane and horizontal out-of-plane loading
Authors: Lampropoulos Andreas , Tsioulou Ourania , Dritsos Stephanos
Published: February 2021

The structural upgrade of existing Unreinforced Masonry (URM) buildings is an area with increasingly interest worldwide and especially in low-middle income countries and in earthquake prone areas. The deficiency of the existing URM has been highlighted through collapses and severe damages during recent earthquakes which could be considered as one of the greatest causes of fatalities and economic losses during major earthquakes.

The structural upgrade of existing URM has always been a quite challenging task which is mainly attributed to the relatively poor bond between the ‘new’ material and the existing structures. In this study a novel technique has been investigated by the addition of Ultra High Performance Fibre Reinforced Concrete (UHPFRC) layer together with partial repointing of the conventional mortar in order to increase the shear strength at the interface between masonry and UHPFRC. Numerical analyses have been conducted using Finite Element Analysis (FEA) models that have been calibrated in previous studies using experimental data for UHPFRC. Analyses have been conducted using different values for the thickness of the layer while the mortar-to-bricks and the UHPFRC-to-masonry interfaces have also been simulated. Numerical analyses have been conducted to investigate the axial in-plane and the horizontal out-of-plane behaviour of the strengthened URM specimens.

The numerical results demonstrate that the proposed technique can considerably improve the axial load strength of URM elements. In case of out-of-plane loading, the addition of UHPFRC has been proved to be quite efficient for the improvement of the stiffness and the maximum strength of existing URM structures.