bluuebunny/crossref_metadata_2025 huggingface dataset:
06.05: Wind and Earthquake Damping System for the Isozaki/Allianz Tower in Milan, Italy
Authors: Castellano M. Gabriella , Borella Rudy , Pigouni Aikaterini E. , Infanti Samuele
Published: September 2017

The Isozaki or Allianz Tower in Milan, designed by Arata Isozaki and Andrea Maffei, is one of the three office towers of the CityLife, redevelopment project in the area of the historic exhibition area of Milan. It's a mixed reinforced concrete and steel structure of 202 m height (207 m considering the city ground level) and 247 m including the television antenna. It has 50 storeys above ground, and is the tallest Italian building according to the criteria of highest occupied floor and height to tip. Due to the height and the slender shape (24 m × 60 m in plan) of the tower, the wind and seismic protection system comprises 8 special fluid viscous dampers (FVDs) connected to the base of the building by means of 4 long struts (two for each strut). Each FVDs is characterized by 1304 kN maximum force and ±150 mm maximum displacement capacity. They manage to mitigate the wind effects by suppressing the anticipated wind‐induced accelerations and improving the comfort inside the building. Although Milan is a low seismicity area, the dampers were also designed to sustain also earthquake effects. Therefore, due to the completely different dynamic behaviour of wind and earthquake, the dampers were designed to change behaviour passively, i.e. activated only by the different velocity of the relative displacement between the two ends of the damper. Thus, the velocity exponent α of the typical force vs. velocity constitutive law of the fluid viscous dampers is 1 (linear behaviour) under wind input while is lower than 0.1 (strongly non‐linear behaviour) under earthquake input. Two of the 8 FVDs were subjected to a complete test protocol required by European Standard “Anti‐seismic devices” EN15129:2009 in FIP Industriale Laboratories. This paper describes the FVDs and reports the most important test results, confirming the required behaviour of the devices both under service wind and ULS wind or earthquake.
06.06: Vibration reduction of steel girder bridges: Using shape memory alloy cables
Authors: Liu Airong , Liu Chun‐Hui , Pi Yong‐Lin , Huang Yong‐Hui
Published: September 2017

Torsional vibration caused by moving vehicle loads traversing a steel girder bridge is likely to cause the traffic safety and people comfort problems. This paper investigates the use of cables made of shape memory alloy as the devices of reduction of torsional vibration for steel girder bridges. The shape memory alloy cables are featured by their small volume and expedient installation. To investigate their effect on the vibration of girder bridges, numerical simulation and experimental study are carried out. The results of torsional vibration obtained by finite element simulations are compared with the experimental ones from model testing. The finite element results have good correlation with the experimental counterparts. Comparisons have shown that the finite element model for torsional vibration of steel girder bridges with the shape memory alloy cables being treated as dampers can be used to predict the effects of shape memory alloy cables on the vibration reduction. The finite element and experimental results have shown that shape memory alloy cables can effectively reduce torsional vibrations of steel girder bridges.
06.08: Vibration Control of Novel Passive Multi‐joints Rotational Friction Dampers
Authors: Mualla Imad , Koss Holger
Published: September 2017

This work presents a novel passive friction damper for vibration control of structures.

The device is designed to dissipate input energy and protect buildings, especially large and tall buildings from structural and non‐structural damage during moderate and severe vibration caused by earthquakes or strong winds. The damper is based on a rotational friction concept that was developed by Mualla, I.H.

The devices have a stable energy dissipating behavior. They are flexible in the application, since they only need limited space. The devices can be installed easily. The damping capacity of the devices can be easily increased by adding additional friction layers. The friction damper device proves to be an efficient and economical device for a reduction of dynamic response of structures.

The damper has been tested intensively at the Technical University of Denmark and in Osaka, Japan confirming that the damper performance is:

‐ Independent of forcing frequency within applicable range

‐ Linearly dependent on displacement amplitudes

‐ Linearly dependent on normal forces

‐ Very stable over many cycles

Furthermore, a numerical model of the 4‐joint damper has been developed based on an analytical derivation of the internal work in the damper. A comparison of results obtained from the experimental work and numerical model showed that the model well represented the behavioral characteristics of the damper, and that the dissipated energy was reliably predicted.

So far several models of the rotational friction dampers that are supplied by Damptech A/S have been installed in many projects in Japan, among them Japan tallest building and in other countries around the world. The paper provides a number of show cases demonstrating versatile application of rotational friction dampers (RFD).
07.07: Numerical study of screw fasteners in built‐up CFS chord studs
Authors: Kechidi Smail , Fratamico David C. , Bourahla Nouredine , Castro José M. , Schafer Benjamin W.
Published: September 2017

This paper presents the development of finite element (FE) models for advanced analyses of screw connected and axially‐loaded back‐to‐back, built‐up cold‐formed steel (CFS) chord studs. Results are validated using column test data from displacement‐controlled experiments conducted at Johns Hopkins University. Shell finite element‐based models have been assembled in ABAQUS and include non‐linear geometric, material, and contact behavior. A unique feature of the developed models is the simulation of screw‐fastener connections using a user‐defined element (UEL), which can reproduce strength and stiffness deterioration under a monotonic load as well as the pinched response that occurs in the shear behavior of these connections when subjected to cyclic loading. Connection stiffness and strength data from pure shear tests of steel‐to‐steel and steel‐to‐oriented strand board (OSB) connections are used in the formulation of the subroutine and is discussed herein. Seventeen monotonic and concentric compression tests on two different built‐up CFS cross‐section sizes with varying fastener layouts and sheathing conditions were simulated. The buckling, peak, and post‐peak behavior of the built‐up columns is examined. Good agreement was reached among experimental and numerical results in terms of load‐deformation histories, as well as buckling and failure modes. Results indicate that under the tested end boundary conditions there is no significant boost in axial capacity with the addition of member end fastener groups at the top and bottom of the built‐up columns in common sheathed configurations; further, the response of screw fasteners remains elastic up until the post‐peak regime, revealing conservatism in the built‐up column fastener layout currently required by AISI S100‐16 section I1.2. The goal of this study is to improve existing design guidelines in which all relevant failure modes are considered in the design of built‐up CFS columns. In addition, the characterization of monotonic and cyclic behavior of columns is sought so that chord stud buckling limit states are captured in simulations of shear walls.
07.11: Rotational behavior of cold formed steel beams connected through clip angles
Authors: natesan vijayakumar , madhavan mahendrakumar
Published: September 2017

Cold – formed steel (CFS) members are gaining importance as a material of choice for low‐rise residential construction in the developing world. The floor system used in such structures are constructed using CFS beams in a grid pattern. The CFS beams are typically connected utilizing clip angles whose rotation and ductility behavior is the focus of the present research. A total of 24 numbers of beam to beam connections with different connection configurations were tested to investigate the performance of clip angle connections concerning moment and rotational stiffness. The connection configuration parameters studied include four different aspect ratios for loaded leg, 3 different aspect ratios for anchored leg and two different thickness of clip angle. It was observed that the ultimate load of the clip angle bolted connection depends on the thickness and aspect ratios of clip angle. The maximum rotational stiffness value was obtained in the connection configuration 1.5 1×3.2‐3. The rotational stiffness versus percentage of ultimate moment depends on the anchored leg aspect ratio. The strain deformation measured in both legs of the clip angle and on both sides of the member connection between the loaded member and anchored member and on the anchored member helps to describe the clip angle behavior and loaded CFS member.
07.17: Design methods for drive‐in steel storage racks
Authors: Shaheen Mahmoud S.A. , Rasmussen Kim J.R.
Published: September 2017

The European racking federation design guidelines FEM10.2.07 (2012) contains provisions for the analysis and design of drive‐in and drive‐through racks. It specifies different methods for carrying out the design, and the design verifications differ depending on the method chosen. However, there appears to be no published studies that compare the analysis and design methods specified in FEM10.2.07 and give recommendations for using a particular method over the other. In addition, the design guidelines are unclear about the definition of the effective length to use in the design of uprights. Depending on the way the effective length provisions are interpreted it leads to significantly different solutions. This paper studies the different design methods specified in FEM10.2.07 and exemplifies the differences, advantages and disadvantages of each method, and puts forward recommendations for design depending on drive‐in rack characteristics.
07.21: Experimental setups for the measurement of the rotational restraint provided to cold‐formed Z‐purlins by sandwich panels
Authors: Balázs Ivan , Melcher Jindřich , Belica Andrej , Oly René , Misiek Thomas
Published: September 2017

Sandwich panels supported by purlins are widely used as the main load bearing part of roof systems of steel buildings. Sandwich panels provide lateral and rotational restraint to purlins which positively influences their resistance. Lateral restraint given by sandwich panels is equal for both the downward and uplift loads applied on the panel's surface, though the rotational restraint may have different character. The uplift load reduces contact area between the panels and purlins which can result in smaller restraint value.

ECCS Publication N° 135/CIB Publication 379 states, the rotational restraint for uplift shall be determined by tests with the recommended setup, otherwise a zero value has to be considered. The recommended setup, originally developed by Joachim Lindner, was also used for the large EASIE testing program which was the base of the aforementioned recommendation. The test setup from EN 1993‐1‐3, originally developed by Teoman Peköz for tests with cold‐formed purlins and corrugated sheeting, has been considered as inappropriate for sandwich panels because it does not consider effects from transverse load.

During the EASIE test program only hot‐rolled purlins were tested and therefore evaluation did not take into account section distortion which is negligible for hot‐rolled sections. The application of the test results for cold‐formed purlins and conclusion related to the rotational restraint under uplift load therefore required re‐confirmation by tests with cold‐formed purlins.

The experimental research, to determine the rotational restraint given to cold‐formed Z purlins by sandwich panels, was performed at Brno University of Technology (BUT) in collaboration with Astron Buildings S.A. (Astron). Sandwich panels with direct fastening and hidden fastening, with PUR/PIR and mineral wool core were tested. ECCS/CIB test setup with the application of a torsional moment and a modified setup with the application of a direct force were used. Several tests were additionally done with the setup described in EN 1993‐1‐3. The creep effect was investigated as well. Based on the tests results, available test setups for cold‐formed purlins were weighted and commented. The correction of the current draft of EN 1993‐1‐3 was proposed.
07.25: Assessment of the utilisation of corrugated cardboard as a core material for sandwich panels
Authors: von der Heyden Aaron , Lange Jörg
Published: September 2017

Sandwich panels became well‐established in industrial structures within the last 25 years, because they are light weight, cost efficient and provide a complete building envelope. Usually the panels consist of a thick core layer with a low density in between two thin metal face sheets. Both the face sheet and the core layer carry loads. While the face sheets provide high strength for axial stresses, the function of the core is to carry shear stresses and support the thin face sheets against wrinkling normal to their plane. Furthermore the core material acts as thermal insulation.

The two most commonly used core materials for sandwich panels, polyurethane foam and mineral wool, have significant disadvantages concerning ecology and health compatibility. They are either petroleum‐based or fabricated with binders, which are based on non‐renewable resources. The energy consumption during the production process is very high. These core materials are hardly recyclable and their disposal is connected to great expense and environmental pollution.

Corrugated cardboard has not only good thermal insulation properties. It also has a high load‐carrying capacity by being low‐costs and lightweight. The aim of this research project is the assessment of the utilisation of corrugated cardboard as a new core material for sandwich panels in building industries. The core is assembled by many layers of commercially available corrugated cardboard, glued together with organic binders. Mechanical and building physical properties are obtained for different kinds of corrugated cardboard as well as for different orientations. The material behaves anisotropic and thus, depending on the orientation of the core stiffness and strength could be determined, which are similar or even higher than these of common core materials. In this paper the results of so far conducted experimental investigations are presented and an outlook on future approach is given.
07.29: A unified methodology for the modelling of steel behaviour: An application‐oriented methodology
Authors: Hassan Muhammad Shariq , Salawdeh Suhaib , Goggins Jamie
Published: September 2017

This paper presents a universally applicable methodology for the development of a material model for steel subject to static tensile loading. It is the first methodology ever presented in a unified format in the context of steel behaviour, and is critical for the ductile designing of steel elements. Hook's model, Hollomon's model and the Modified Weighted Average model (MWA) are extensively used in literature to model the linear elastic, strain hardening and necking behaviour of steel, respectively. In this paper, these three empirical models have been unified and linked empirically in order to format a design approach.

In order to demonstrate the applicability of the design approach, a set of coupon test data, which reflects the material properties of 40×40×2.5, 20×20×2.0, and 50×25×2.5mm cold‐formed steel hollow specimens, is used. The material model is utilised in finite element models in simulations of the structural hollow tubes under tension loading. The simulated results are validated in terms of initial yield strength, ductility, material stress‐strain and hysteretic load‐displacement behaviour by using another set of measured data from physical tests, highlights the effectiveness of the methodology.
07.34: Influence of semi‐rigid sleeve joints on the multi‐span purlin design
Authors: Gutiérrez R. , Loureiro A. , Reinosa J.M. , López M.
Published: September 2017

The sleeve joint is a bolted connection frequently employed in the purlins assembly of secondary structure in industrial building, because it facilitates the assembly of the structure. The joint behaviour determines the purlin structural behaviour.

Recently, authors have proposed a simple approach to predict the stiffness and strength of the sleeve connection, depending on the lap length to depth ratio [1]. It includes rotational springs on the joint bolt lines, actuating in a coordinated way.

In the present paper, multi‐span purlin models including the semi‐rigid nature of the joints are developed. They consist on beam and rotational spring finite elements, based on the previous approach. The joint behaviour influences the stresses and deformations developed by the purlin, which can be analysed, allowing for safety design in elastic range.

The multi‐span purlin design with sleeve joints are studied, employing a model that includes the realistic behaviour of joints. The objective is to address the minimum lap length to depth ratio of the sleeve joints, needed for a confidence purlin design. This work is proposed in the framework of the optimized multi‐span purlin design with cold formed profiles, according to the European standards.
07.37: Development in calculation of stressed skin effect upon experimental and numerical research results
Authors: Lendvai Anita , Joó Attila László
Published: September 2017

The opportunities of improvement in stressed skin design formulae in the European Convention for Constructional Steelwork (ECCS) publication are reviewed in this paper.

Stressed skin effect is the diaphragm action provided by the in‐plane stiffness of a diaphragm assembly. The diaphragm is composed of panel assemblies transmitting in‐plane forces to the main frames, providing considerable stabilizing effect to the building. The stiffening effect of diaphragm assemblies depends on their components: type of supporting frame, type of sheeting, number of fixings and the connection between sheeting and purlins.

This paper first discusses the results of an experimental analysis carried out in the Structural Laboratory of the Budapest University of Technology and Economics. The experimental programme aimed to study the stiffness of various diaphragm configurations. Based on the results, the principal influencing parameters are identified. The results confirm that the eccentricity of the connected members – that is out of consideration in current Eurocode provisions – play significant role in the stiffness, and thus it should be considered in design for stressed skin effect. The experimental results also served as a basis for numerical model development and calibration. The verified FE model is capable for numerical simulation of any kind of diaphragm assembly. The paper introduces the results of a parametric study aiming to extend the real experimental results by further virtual experiments.

Based on the experimental and numerical results, modifications are proposed to the current Eurocode provisions, in order to capture all influencing parameters and thus to extend the applicability of the standard design model for “non‐standard” configurations that are commonly installed in practice as well.
08.07: Performance and capacity of composite “mega columns” with encased hot rolled steel sections
Authors: Bogdan Teodora , Gerardy Jean–Claude , Davies Donald W. , Popa Nicoleta
Published: September 2017

Steel reinforced concrete (SRC) columns are widely used in high‐rise buildings, since they provide larger bearing capacity and better ductility than traditional reinforced concrete (RC) columns. This type of structural system is not currently explicitly addressed in the actual design codes.

The paper aims at presenting the behaviour of a new configuration of mega columns – isolated steel reinforced concrete (ISRC) columns. A two‐phase test was conducted on scaled ISRC columns designed based on a typical mega column of a super high‐rise building. Phase 1 of the study includes six 1/4‐scaled ISRC columns under static loads: every two of the specimens are loaded statically with the eccentricity ratio of 0, 10%, and 15%, respectively. Phase 2 of the study includes four 1/6‐scaled ISRC columns under quasi‐static loads: every two of the specimens were loaded under simulated seismic loads with the equivalent eccentricity ratios of 10% and 15%, respectively. A finite element analysis (FEA) was conducted as a supplement to the physical tests to provide a deeper insight into the behaviour of “mega columns”. An extended Plastic Distribution Method is defined to evaluate the capacity of the specimens. The method is based on simplifications similar to those proposed in EC4 [1]. The scope of this latter standard is limited to the consideration of one single steel profile. The method is validated by comparisons with experimental and with numerical simulation results using advanced finite element programs, showing a good accuracy in results.
08.19: Tests on concrete‐filled double skin tubular beams with circular stainless steel outer tubes
Authors: Wang Fangying , Young Ben , Gardner Leroy
Published: September 2017

A test program on concrete‐filled double skin tubular (CFDST) beams with austenitic stainless steel outer tubes and high strength steel inner tubes is presented in this paper. A total of 22 four‐point bending tests was carried out to study the behaviour and strengths of CFDST beams. The stainless steel outer tubes were circular hollow sections (CHS) with average diameter‐to‐thickness ratios of 56.8 and 48.5, and the measured 0.2% proof strengths of 276 MPa and 300 MPa, respectively. The high strength steel inner tubes were also circular hollow sections (CHS) with diameter‐to‐thickness ratios ranging from 5.0 to 22.8, and corresponding measured 0.2% proof stress ranging from 433 to 1029 MPa. The annuli were filled with concrete with three different concrete cylinder strengths of 40, 80 and 120 MPa. The moment capacities, moment–curvature relationships and failure modes of the beams are reported in this paper. It should be noted that currently there are no design provisions for concrete‐filled stainless steel members. The test strengths were therefore compared with the moment capacity predictions in existing design codes (the European Code and American Specification) for concrete‐filled carbon steel tubes. The comparisons revealed that both design codes provide very conservative resistance predictions.
08.29: Experimental investigation of concrete‐filled double skin tubular stub columns with ferritic stainless steel outer tubes
Authors: Wang Fangying , Young Ben , Gardner Leroy
Published: September 2017

An experimental investigation of concrete‐filled double skin tubular (CFDST) stub columns with ferritic stainless steel outer tubes and carbon steel inner tubes is presented in this paper. A total of 14 tests was carried out to study the axial compressive behaviour and strengths of CFDST specimens. The outer tubes were cold‐formed from ferritic stainless steel material (grade 1.4003) into rectangular hollow sections (RHS) with depth‐to‐thickness ratios ranging from 26.1 to 42.1, while the inner tubes were cold‐formed from carbon steel (grade S235) into square hollow sections (SHS) with width‐to‐thickness ratios ranging from 7.5 to 13.5. The gaps between the outer and inner tubes were filled by concrete with three different nominal cylinder strengths of 40, 80 and 120 MPa. The columns had different lengths so that the length‐to‐depth ratio remained at a constant value of 2.5. The CFDST specimens were subjected to uniform axial compression. The column strengths, load‐axial strain relationships and failure modes were evaluated in this paper. The test strengths were then compared with the strengths calculated from the existing design codes, where the guidance given in European Code, Australian Standard and two American Specifications for concrete‐filled columns were used. It is shown that current design rules provide conservative predictions for the resistance of CFDST stub columns with ferritic stainless steel outer tubes.
08.30: Experimental investigation and specific behaviour of X‐HVB shear connectors in prefabricated composite decks
Authors: Gluhović Nina , Marković Zlatko , Spremić Milan , Pavlović Marko
Published: September 2017

Construction industry is constantly facing new demands towards fast construction and smallest possibly quantity of work at the construction site. These increasing demands, in the field of composite construction of buildings and bridges, resulted in development of different types of prefabricated composite decks during decades and group arrangement of different types of shear connectors. Positioning of shear connectors into envisaged openings of prefabricated composite decks contributes to smaller quantity of concrete needed to infill openings of prefabricated composite decks. Composite action between steel profile and concrete decks can be achieved using X‐HVB shear connectors with powder‐actuated fasteners. Anchorage mechanisms developed between steel profile and fasteners during installation process of powder‐actuated fasteners are resulting in composite action between steel and concrete. Relatively simple and fast installation process, without requirements for additional equipment and electrical power on the site is characteristic for this type of shear connectors. Experimental investigation of X‐HVB shear connectors in prefabricated composite decks through standard push‐out tests, according to EN 1994‐1‐1 is presented in this paper. Shear connectors are positioned at the envisaged openings of prefabricated composite decks at the minimal longitudinal and transversal distances, recommended by the manufacturer. Two different orientations of shear connectors, forward and backwards to shear force direction are experimentally investigated and presented in this paper. Experimentally obtained characteristic shear resistance are compared with recommendations given by manufacturer. Characteristic slip at failure obtained from experimental investigation is compared with requirements given in EN 1994‐1‐1 in order to determine if this type of shear connector is considered as ductile. Eight specimens in two series are experimentally investigated through standard push‐out test. Different characteristic shear resistance and different failure modes are obtained for forward and backward orientation of shear connectors. Experimentally obtained results from standard push‐out tests for different orientations of shear connectors are compared with results obtained from extensive numerical analysis performed in Abaqus.
08.38: Experimental characterisation of the flexural behaviour of rubberized concrete‐filled steel tubular members
Authors: Silva António , Jiang Yadong , Castro José Miguel , Monteiro Ricardo
Published: September 2017

The main objectives of the research presented in this paper are to investigate the flexural behaviour of Concrete Filled Steel Tube (CFST) columns made with Rubberized Concrete (RuC) and to identify the behavioural differences between this type of composite members and typical (standard concrete) CFST members. The influence of the rubber aggregate replacement ratio on member strength, ductility, and energy dissipation capacity is assessed. The paper begins with a description of the preparation and development of the experimental campaign, which involves the testing of 36 composite specimens (28 RuCFST and 8 standard CFST), and a single circular hollow steel tube. The selection of the specimens took into account a number of geometrical and material parameters, namely the shape of the cross‐section (circular, square and rectangular), the cross‐section slenderness and the rubber aggregate replacement ratio. A novel testing mechanism was developed as a part of an innovative testing setup, aimed at reducing both the cost and preparation time of the specimens. The columns were tested under both monotonic and cyclic lateral loading, combined with different levels of axial compression. The monotonic results were compared with the expected flexural capacities according to Eurocode 4, and the cyclic results were used to gauge the sectional slenderness limits of Eurocode 8 for different ductility classes. The test results obtained are indicative of the reduced influence of the type of concrete infill on the monotonic and cyclic flexural behaviour of these composite members, and also allow concluding that Eurocode 4 is conservative in predicting the capacity of the tested specimens. Moreover, it was found that the cross‐section slenderness does not have a significant influence on the monotonic and cyclic behaviour of the specimens, pointing out for the possible relaxation of the cross‐section slenderness limits currently specified in Eurocode 4 and 8.
08.39: Experimental investigations on performance enhancement of composite steel concrete shear walls by using steel fibre reinforced concrete
Authors: Dan Daniel , Stoian Valeriu , Florut Sorin‐Codrut , Fabian Alexandru , Boita Emanuela
Published: September 2017

The paper presents further results of an experimental program that was conducted at the Politehnica University Timisoara, studying the behaviour of Composite Steel‐Fibre‐Reinforced‐Concrete shear Walls (CSFRCW) with partially encased profiles. Use of such shear walls represents a widespread solution for providing a lateral load resisting structural system, especially in the case of medium and high‐rise buildings placed in seismic areas. As previous theoretical and experimental studies have proved the performance of such system, the foremost objective of the experimental program consisted in identifying innovative solutions for composite steel‐concrete shear walls with enhanced performance, as steel fibre reinforced concrete which was used in order to replace traditional reinforced concrete. The program consisted in tests on 6 specimens designed as 1:3 scale steel‐concrete composite elements, leading to an experimental matrix that enabled complex comparisons of various solutions. Thus, a steel reinforced concrete shear wall (without any encased profiles) was used as reference, configuration/arrangement of steel profiles and ratios of steel fibre reinforcement were varied within the other five specimens. The effective stiffness, strength and ductility is evaluated using the experimental results.
08.40: Numerical investigation of mechanical properties of multi‐planar concrete‐filled steel tubular joints
Authors: Chen Juan , Nie Jianguo , Zhou Chengye
Published: September 2017

With the development of large span and heavy load modern engineering, concrete‐filled steel tubular structures appear constantly. The joints of these structures are mostly multi‐planar joints. In order to solve the problem of lacking of the investigation of multi‐planar concrete‐filled steel tubular (CFST) joints, the mechanical behaviour of CFST KK joints were studied through refined finite element simulation. Accurate finite element models of CFST KK joints were established by considering the material nonlinearity, the geometry nonlinearity, and the contact nonlinearity between the tube and the concrete. The spatial effect of multi‐planar joints was be obtained by comparing with planar joints. The FEA results showed that, the multi‐planar carry‐over effects had the maximum effect for the 60° CFST joints, the strength of multi‐planar joints decreased compared with the planar joints, and the stiffness of them did not vary substantially. While for the 90° CFST joints, both the strength and stiffness of multi‐planar joints did not vary substantially with the planar joints. This research can provide scientific basis for the design of multi‐planar CFST joints, and effectively promote the application of CFST structures.
08.42: Composite behaviour of headed stud shear connectors with BubbleDeck flooring
Authors: Denoord Luke , Varsani Harshad , Tan Ee Loon , Singh Balbir
Published: September 2017

BubbleDeck is a biaxial voided concrete slab product that was developed in the 1990's by Danish engineer Jorgen Breuning. The technology is similar to other modern voided slabs such as U‐Boot and Cobiax, however it has its distinct advantages. These advantages include decreased construction time, material costs savings and the environmental benefits. Composite steel‐concrete construction is an increasingly common construction method in the modern building industry. This process involves utilising the high tensile strength of steel and the high compressive strength of concrete to create composite members with structurally favourable characteristics. In order to join the steel and concrete components, a connection is needed to stop slip occurring at the interface and allow the materials to behave as a single element. The most common connection is the end welded headed shear connector, known more commonly as the shear stud. Shear studs have a recommended design capacity as specified by suppliers and connections are designed according to these capacities. Standards such as Eurocode and Australian Standards have a guide for composite connection design; however, these guides do not pander to new technologies such as BubbleDeck. As such engineers and designers often have difficulty and uncertainty in designing these types of connections. Through analysis of composite connections and BubbleDeck specifications, a series of test specimens has been designed. Specimens were composed of concrete, steel reinforcement, a steel section, shear studs and BubbleDeck void formers. These specimens were tested according to the Eurocode 4 standard to study the interactions of the BubbleDeck voids and the headed shear connectors. Experimental results and observations were recorded during and after the test specimens were tested. Results suggested that the overall shear capacity or BubbleDeck slabs in composite beams was approximately 5 to 10 % less than the capacity of equivalent solid slabs. The observations showed that the proximity of headed shear connectors to voids did not have a significant effect on the capacity of the connection, with respect to the arrangements tested.
08.49: Comparison of headed studs with perfobond shear connectors – experimental and numerical analysis
Authors: Spremić Milan , Gluhović Nina , Marković Zlatko , Dobrić Jelena , Filipović Aljosa
Published: September 2017

Different types of shear connectors which assure composite action between steel profile and concrete slabs have been developed during decades, considering different shapes, installation equipment and installation process. Also, three main characteristics of shear connectors, shear resistance, stiffness and ductility are specific for each type of shear connector. Widely used shear connectors for composite constructions of buildings and bridges are headed studs and different types of perfobond shear connectors. Different behaviour of these types of shear connectors, mainly reflected in unsatisfactory behaviour of headed studs resulted from fatigue problems, reflects in their various applications. Numerous experimental and numerical investigations performed with headed studs and perfobond shear connectors through standard push‐out tests resulted in development of design procedures which are proposed by different authors or can be found in current design codes such as EN 1994‐1‐1, ANSI/AISC‐360‐05 and JSCE. Comparison of heads stud's and perfobond shear connector's beahviour through experimental results of standard push‐out tests are presented in this paper. Experimentally obtained shear resistance of four headed studs with 16 mm diameter and 100 mm height, positioned in one row into envisaged openings of prefabricated composite decks, with shear resistance of perfobond shear connectors are compared. Main differences in respect of ductility, stiffness and different failure modes which can be noticed for these types of shear connections, obtained from experimental investigation are analyzed in this paper. Comparative analysis includes different shapes, dimensions and specimen's layout of perfobond shear connectors, experimentally investigated through standard push‐out tests which results are available in different literature. Numerical analysis included perfobond shear connectors positioned into envisaged openings of prefabricated composite decks with same dimensions and material properties which are used for numerical analysis of considered headed studs shear connection and which are obtained from experimental investigation. Shear resistance obtained from numerical analysis of perfobond shear connectors are compared with design procedures developed from different authors.
08.56: Horizontal distribution of concentrated loads in ComFlor210 composite slabs
Authors: Abspoel Roland , Stark Jan , Prins Henk
Published: September 2017

Composite slabs are built up with a thin‐walled cold‐formed steel deck and interconnected with a concrete topping, see Fig.a).

a) Composite slab; b) Cross‐section ComFlor210

image

Steel decks can be subdivided into two groups, shallow decks and deep decks, see for an example of a deep deck Fig. b). In EN1994 [1] a subdivision is given based on the spacing of the webs. EN1994 covers only narrow spaced webs which are defined by the ratio, where is the width of the upper flange and is the distance between centres of adjacent ribs. The recommended value for the upper limit of this ratio is br/bs, where br is the width of the upper flange and bs is the distance between centres of adjacent ribs. The recommended value for the upper limit of this ratio is br/bs = 0.6. ComFlor210, a deep steel deck produced by Tata Steel UK, has a ratio br/bs = 425/(546 + 54) = 0.71 > 0.6 and is consequently not covered in EN1994.

Composite slabs are designed to transfer loads in one direction i.e. the longitudinal direction of the ribs. However when a concentrated load is acting on a rib, part of the load will be distributed to adjacent ribs. The slab is to be considered as an orthotropic plate.

In clause 9.4.3 of EN1994‐1‐1 simplified rules are given for the determination of the effective width. However, as explained above, these rules are only applicable to shallow decks. At Delft University of Technology a research project was carried out to gain better understanding in the horizontal distribution of concentrated loads in deep composite slabs – see reference [2]. In the framework of this project a series of three test specimens was tested in the Stevin II laboratory.
08.57: The friction investigation of CFRP confined CFST specimens with modified concrete
Authors: Evirgen Burak , Tuncan Mustafa , Tuncan Ahmet
Published: September 2017

Nowadays, concrete filled steel tube (CFST) composite members have in wide range application areas such as transverse beams, piers, slender columns, stub columns, wind turbines etc. around the world. The frictional behavior between concrete and steel tube has a vital role in selection of required size and materials during the laboratory experiments, in‐situ applications and modelling studies. In this study, 16 CFST members were subjected to push out tests within the aim of determination the effect of carbon fibres reinforced polymer (CFRP) confinement and modified concrete at the same time. Modified concrete indicates some mechanical additives are inside the concrete for instance steel fibres, polypropylene fibres and crumb rubber. Furthermore, external CFRP confinement was applied with three different arrangements on the outside circumference of the steel tube. Frictional stress created on the lateral interaction surface ranges between 0.18 MPa and 0.63 MPa due to maximum striping force. Maximum frictional strength was observed on the unconfined reference concrete. Although CFRP application seriously increased the axial strength of composite sections, this process decreases the frictional strength between concrete and steel tube, unexpectedly. Therefore, considering different frictional coefficient emerges as a foregone conclusion during the design procedure of CFRP confined CFST sections.
08.61: A new approach for the serviceability limit state design of composite steel‐concrete slabs
Authors: Ranzi Gianluca
Published: September 2017

Composite floors are a well‐established cost‐efficient and effective form of construction. They combine the advantages of two flooring systems that consist of post‐tensioned slabs in concrete structures and of composite slabs in steel structures. These flooring systems include thin‐walled profiled steel sheeting, non‐prestressed reinforcement, concrete and prestressing strands in post‐tensioned slabs. The particularity of composite slabs rely on the ability of the profiled steel sheeting to act as permanent formwork and, once the concrete has hardened, as external reinforcement.

This paper provides a brief overview of a new service model for the design of composite and post‐tensioned steel‐concrete floor systems. The serviceability limit state requirements are important for composite floor applications because they usually represent their governing criteria. The proposed approach focuses on the serviceability limit state requirements associated with deflections and places particular attention on the influence of shrinkage on the overall structural response. Recent research has highlighted the occurrence of a non‐uniform shrinkage profile through the composite slab thickness that originates form the inability of the concrete to dry from its underside due to the presence of the profiled steel sheeting. The proposed procedure is validated against selected experimental results available in the literature for composite and post‐tensioned composite slab samples.
09.09: Experimental fatigue analysis of high strength steel structures
Authors: Mecséri Balázs József , Kövesdi Balázs
Published: September 2017

There are contradictional information in the previous studies regarding the relationship between the fatigue strength and the yield strength in case of steel structures. Several previous test result show that the fatigue strength of as‐welded specimens do not depend on the yield strength of the base material. However, several studies show that the fatigue detail class of HSS structure can be higher than for structures made form NSS material for the same structural detail. Collecting the previous fatigue test results of cruciform and flange gusset structural details the effect of the yield strength on the fatigue behaviour is studied. Additional laboratory test program with 32 test specimens is performed to investigate the fatigue behaviour of structural details typically used in bridges produced from HSS and NSS material. For cruciform welded joints the test results show clear correlation between the yield strength and the fatigue life time. For flange gusset joints this relationship cannot be observed. In addition, post weld treatment of the flange gusset plate joint is studied. Using the results of the fatigue tests the fatigue lifetime increase applying the grinding type post‐weld treatment is evaluated.
10.18: Material properties of high strength steel under fire conditions
Authors: Winful Dorothy A. , Cashell Katherine A. , Afshan Sheida , Barnes Adrienne M. , Pargeter Richard J.
Published: September 2017

This paper is concerned with the material characteristics of various commercial high strength structural steels (yield strengths between 460 and 700 N/mm2) under fire conditions. The paper proceeds with a description of the experimental programme which includes two different grades of high strength steel. The aim of this research is to assess (i) the mechanical properties at elevated temperature through tensile testing to support the safe design of fire resistant structures made from high strength steel and (ii) the effect of chemical composition and processing route on the microstructure through a detailed metallurgical investigation. In this paper, a series of isothermal and anisothermal elevated temperature tests are conducted on two commercially‐available steel grades (S690QL and S700MC). Following a detailed description of the tests, the results are analysed to determine strength and stiffness reduction factors at elevated temperatures and these values are compared with literature and EN 1993‐1‐2 (2005). It was found that the results for S700MC, for which there is limited data in the literature, showed better strength retention properties than S690QL at elevated temperatures. The results also showed that under isothermal conditions, the guidance for the elastic moduli of these materials may be unconservative and overly optimistic.
10.20: Numerical simulation of the behaviour of steel members with damaged SFRM fire protection coatings at elevated temperatures
Authors: Zografopoulou Kalliopi , Mistakidis Euripidis
Published: September 2017

In this study an integrated approach to the problem of the fire behaviour of steel members with damaged cementitious SFRM coatings is attempted, by modelling numerically both the mechanical damage of the coating applied on a steel member and the impact that this damage has on the structural behaviour of the steel member under ISO‐834 thermal loading. The numerical study is performed on a steel plate coated with cementitious fire resistive material, and is based on literature results for a test specimen that has been submitted to flexural bending, to study the damage mechanisms of the SFRM coating and the interface bond. Initially, the numerical analysis is performed in normal temperatures to simulate the mechanical damage in the interface and the body of the SFRM coating under flexural load. Then, based on the developed numerical structural model, parametric models of steel plates with SFRM coating that has sustained various degrees of damage are submitted to combined structural and ISO‐834 thermal loading. Coupled thermo‐mechanical analysis is performed to examine the temperature evolution in the steel plate and the evolution of the vertical displacement and the plastic deformations during a 2‐hour thermal exposure.
10.25: Numerical fire tests on the columns of the Cardington steel‐framed building
Authors: Rocha Fabio M. , Albuquerque Gabriela L. , Rodrigues João Paulo C. , Laim Luis
Published: September 2017

The behavior of steel and composite steel and concrete columns with restrained thermal elongation in case of fire has been studied for several years. The influence of the restraining to thermal elongation may, in some cases, have a pernicious effect leading to the sudden collapse of the column but in other cases, for higher values of rotational stiffness, the collapse of the column is slow and gradual.

In this paper are presented the results of numerical simulations performed on some of the columns of the BRE's Cardington Steel Framed Building calibrated with results from experimental tests carried out on this building structure by the third author of the paper. They were compared gas and steel temperatures, strains, displacements and rotations of the columns ends.

The results of the experimental tests were used to calibrate a numerical model of the entire building structure. In these numerical simulations, performed with the finite element program Abaqus, was considered the fire at different locations in the building. They were calculated strains and displacements at critical points of the structure.

This work allowed to study the influence of the thermal restraining on the behavior of the columns when subjected to a localized fire. It could be observed a redistribution of forces along the structure in such a way that the collapse of a column did not affect the stability of the whole building. However the collapse of more than one important column could lead to the collapse of the entire structure.