bluuebunny/crossref_metadata_2025_split huggingface dataset:
Flexural behavior of hybrid ultra-high-performance concrete
Authors: Danha L S , Abdul-hussien Z A , Abduljabbar M S , Yassin L A G 
Published: March 2020

Abstract
Ultra-high performance fiber reinforced concrete has superior mechanical and structural properties but the major drawback of this new construction material is its high cost. This research presents an experimental study to investigate the flexural behavior of hybrid ultra-high-performance concrete with different steel fibers’ volume fractions, cast in full and partial depths of specimen’s cross sections to exploit the advantages of steel fibers in optimal way. The variables studied included the percentages of steel fibers used (0, 1, 2 and 3) % and the fraction of depth containing the steel fibers (0.25, 0.5, 0.75 and 1). Experimental results show that the failure load increases with the increase in the fraction of depth where the steel fibers were distributed. This increase was more significant as the fraction of depth increases from 0.25 to 0.5 and 0.75. As it reached the 0.75 the increase was none pronounced, and the failure load was almost similar to that of full depth. Therefore, it can be concluded that the maximum effective fraction of depth would be 0.75. It was noted that the different distribution of the same amount of the steel fibers within the depth of the section greatly affects the specimen load capacity and using the steel fibers in the tension zone effectively enhances the flexural performance of UHPFRC. The results also indicate that increasing the steel fiber volumetric ratio from 0% to 1%, 2% and 3% the percentages of increase in the failure load (Pf) with respect to the control specimen were 156%, 261% and 389%, respectively.
Effective length and area of bolted steel plates attached externally to strengthen reinforced concrete beams
Authors: Abtan Yaarub G 
Published: March 2020

Abstract
In this research an investigation has been done on eight reinforced concrete beams. Each beam was strengthened by bolted steel plates attached to their bottom side, of which length and thickness ratio varied, except one beam which has been tested without steel plate as controlling test. Two limits have been introduced upon the maximum plate area used and its minimum length. The first limit is to insure a ductile tension failure, and the latter is to prevent loss of interaction between the two components. Bolts with head were used to provide suitable connection through the specimens of concrete beams and the steel plates through predrilled holes in the steel plates. All beams have similar dimensions and tested simply supported over an effective length of 1600 mm and loaded with central load. Test results show that the plated beam gain an increase in strength over that of unplated beam of about 145%. Also, beams with relatively thin plates, the plate length has little effect upon the ultimate strength, however, for beams with thicker plates the results show a decrease in strength of about 16%.
Development of steel structure connections for seismic resistance using composite steel bolts/rubber
Authors: Ali Suhaib. J. , Ibrahim Amer M. , Shafeeq Sarmad 
Published: March 2020

Abstract
This study scoped to develop the connections of steel structures using composite steel bolts/rubber to connect beam-to columns joints of steel structures instead of conventional steel bolts. Four steel plane portal frames were tested under horizontal cyclic quasi-static load. The study included testing different diameters of composite steel bolts/rubber: 0.5dbolt
, 1.0dbolt
, and 1.5dbolt
, that are used to connect the beam with columns and these results were compared with traditional beam-to columns connections without rubber. The rubberized connections are working at high structural standards through reducing the effect of the stresses resulting from the earthquakes by absorbing damping process. They protect the bolts that are used in joints of steel structures from corrosion due to friction, and they are economically feasible because the rubber that was used for covering the bolts is taken from old tires. The experimental tests proved that using the rubber material around the bolts as much as one - half times bolt diameter raises the specimen’s resistance by 166.66%, increases the displacement by 163.30%, and reduces the strain by 48.13%, as compared with bolts that do not have a rubber (steel bolts only). All these results will be discussed in detail in this report.
Semi-Active Control Performance Index for magneto-rheological dampers considering s-structure interaction
Authors: Yanik Arcan 
Published: March 2020

Abstract
In this study, an instantaneous optimal control performance index for structures with magneto-rheological (MR) dampers is analytically defined. Absolute acceleration and absolute velocity feedback are implemented to this simple performance index. The performance index is another application of instantaneous optimal control algorithms. A three story structure incorporating an MR damper is presented as a numerical example. Modified Bouc Wen damper force model is used for obtaining the MR damper force. The electrical current need for the operation of the MR damper is taken into account by using a piece wise invertible MR damper model. Near fault earthquakes are used in the dynamic simulations. Seismic energy-based evaluations are carried out. Uncontrolled structural response reduction performance and power requirement of the MR damper is investigated. The analysis shows that proposed performance index is effective in reducing uncontrolled structural seismic responses.
Adaptation of local wisdom in contemporary mosque design for achieving good building physics and earthquake resistance
Authors: Sari Laina Hilma , Izziah  , Meutia Erna 
Published: March 2020

Abstract
The paper aims at proposing the implication of the local wisdom value in designing a contemporary mosque. Local wisdom works successfully in determining a suitable design of vernacular buildings such as traditional mosque. It comprises the considerations on building physics such as sufficient thermal comfort, good daylighting and room acoustics which meets the standard. These parameters are also running fitly with traditional wooden structure of the mosque which is resistant against the earthquake. This article analyses two old mosques in Aceh, Indonesia which are still well standing across their ages. The wooden mosques are Indrapuri mosque in Aceh Besar and Tengku Dipucok Krueng Mosque in Pidie Jaya. The evaluation of the mosques was carried out through observations and some field measurements. This article further examines the adaptations of the local wisdom of the mosque pertaining the buildingphysics and the earthquake resistance that can be applied in the contemporary mosque.
Nonlinear analysis of hybrid reinforced concrete beams under flexural load
Authors: Mohsin Saja Jabbar , Mohammed Nisreen S. 
Published: March 2020

Abstract
In recent years, concrete having a compressive strength of 60 MPa and more is being used for high-rise buildings and long span bridges, but high strength concrete is more expensive than normal strength concrete and became commercially used in engineering construction. This material has to be placed where it should be in order to get an economical consideration.
This study introduces analyses of a new two layers reinforced concrete beam where high strength concrete in the compression zone and normal strength concrete in the tension zone are assumed based on experiences of previous laboratory.
The beam specimens were solved numerically using nonlinear finite element program provided by ABAQUS 6.12 software for static load to verify the same using experiment. An agreement between analysis and experimental results was obtained, and less than 11.4% has been put as acceptable limit.
Seismic Performance Assessment of Istanbul Airport Viaduct According to Turkish Building Seismic Code 2007 by Pushover Analysis
Authors: ŞEngÜl Ecem , GÜler Kadir , GÜler M.Gökhan 
Published: March 2020

Abstract
The goal of this study is to examine and evaluate the structural system and seismic performance of the viaduct which is located the west side of the Istanbul Airport. For this purpose, a three-dimensional structural system of the viaduct is modeled by using SAP2000 (Structural Analysis Program) software. The piers of the viaduct consist of two columns. It connects the terminal building and the parking building to each other, twelve spans and designed according to AASHTO (2002). Earthquake effects are considered in the transverse and longitudinal directions by taking into account the site-specific response spectra. The pre-stressed and precast girders which is used in the deck of the viaduct is designed under bending moment and shear force effects considering service loads, such as self-weight and traffic loads. The pre-stress losses and deflection checks are carried out to satisfy the serviceability conditions of the viaduct deck. The elements of the viaduct, such as pier cap, piers and foundation were designed by considering the vertical and lateral loads, so required cross-sections and reinforcement area are determined. In the present paper earthquake performance evaluation of the viaduct is accomplished according to the Turkish Building Seismic Code 2007 (TBSC 2007). Performance evaluation of the viaduct is carried out by applying static pushover analysis, one of the non-linear analysis methods, is applied to the pier located at the middle axis of the viaduct. Under lateral loading, the plastic hinges are developed at the bottom ends of the piers, as anticipated. In the performance evaluation of viaduct piers, the earthquake effect with 10% probability of exceedance over 50 years is considered adopting the parameters given TBSC 2007, whereas the parameters which define the spectrum compared to the Seismic Code of DLH (2007) code. Numerical results are given in tables and figures, comparatively.
Effect of external prestressing strands on the Yielding Stage behaviours of steel beams
Authors: Mahmoud Kamal Sh. , Yousif Mustafa A. , Rasheed Mohammed M. 
Published: March 2020

Abstract
Seven steel beams were tested under one point load to investigate the effect of existence of external prestressing strands on the behavior of steel beams at yielding stage. All steel beams have the same gross area, overall length and the strengthened specimens are employed by two low relaxation strands. The steel beams are divided into two groups according to existence of prestressing strands, the first group involves one steel beam which is considered as a reference beam, while, the second group involves six specimens divided according to the location of prestressing strand (e) at jacking stress (fpj =1120.061 MPa). During the tests, it can be noted that the load strain response for strengthened steel beams are stiffer and the increasing percent of stiffening increases with the increasing of strand eccentricity and the maximum yielding load of strengthened tested beams increases with the increasing of strand eccentricity and the maximum enhancement in yielding load of strengthened tested beams reaches to 126.331% in the OM234 sample compared with the reference beam. Also, it was found that the yielding strain positions changed from bottom flange to the top region for the strengthened tested beams as compared with the reference steel beam and the increasing percent in the yielding to ultimate load ratio (Py/Pu) for the strengthened tested beams increases with the increasing of strand eccentricity at constant applied jacking stress. The maximum percentage increase in yielding to ultimate load ratio (Py/Pu) of strengthened tested beams reaches to 21.06% in the Straight strand profile as defined by OM234 sample as compared with the reference beam.
Behavior of hybrid reinforced concrete columns
Authors: Hamid Marawan M , Yassin Layla A G , Mohammed Alyaa H 
Published: March 2020

Abstract
This paper involves an experimental investigation to study the behavior of short rectangular columns cast with hybrid concrete, to compare the strength, stiffness and toughness provided by the hybrid structural system and the results collected may be used as basic data for future development of design models for this combination of materials.
Seven columns were cast and tested under concentric loading; the variables studied included the diameter of steel bars for both longitudinal and lateral reinforcement. The dimensions of rectangular columns were: 100 mm x 200 mm x 740 mm high. Two columns were cast as full conventional concrete and full reactive powder concrete columns acted as control specimens. The remaining five were cast as hybrid columns having the conventional concrete at the core and surrounded by a 40 mm thickness of reactive powder concrete, with 1% micro steel fiber.
The combination of these two types of concrete into the hybrid concrete columns was very useful because it enhanced the ultimate capacity of the columns with respect to the conventional concrete in about 179% compared to the enhancement produced due to using the reactive powder concrete alone which was 203%, therefore, it was concluded that using this hybrid concrete combination in concrete industry would be more economical than the use of reactive powder concrete; moreover, based on the mode of failure observed, it would be safer to use the hybrid structural system because of the destructive type of failure for columns cast with conventional concrete. Increasing the diameter of the main reinforcement gave an average increase in the percentage of the failure load with respect to the conventional concrete column of about 179% compared to the increase in the diameter of the ties which gave an average increase of 185%; which leads to the conclusion that the effect of lateral reinforcement was more pronounced than the effect of the longitudinal reinforcement in hybrid columns, due to the increase in confinement produced by both the reactive powder concrete cover in the hybrid concrete columns and the ties represented by the lateral reinforcement.
Construction project planning using integration of crashing and concurrency techniques
Authors: Hady Haider Najy , AL-Kindi Luma Adnan , Mahmoud Mahmoud A. 
Published: March 2020

Abstract
Construction Project planning process is considered an essential area in the field of organization and implementation of projects, particularly those needing coordination, great effort and long implementation time. Moreover, project managers are focusing on achieving predetermined objectives. This paper aims to attain certain objectives; cost, time, and number of labourers, in a way that reaches the best satisfied results depending on the importance of each objective. A multi-objective model construction based on project planning in two techniques; crashing technique and concurrency is presented, additionally a new proposed mixed technique titled as Concurrency Partitioning with Crashing Techniques (CPCT). The proposed model is implemented on a Substation of Electrical Power for Transformation plant as a case for studying. The suggested mixed approach (CPCT) provides more desirable results with the multi-objective problem, where both project time and cost are decreased by 19.5% and 2.6%, respectively, while the total number of labourers is increased by 8.8%
Post-Blast Axial Capacity of CFRP Strengthened RC Columns
Authors: Kadhom Bessam , Almansour Husham , Saatcioglu Murat 
Published: March 2020

Abstract
An experimental investigation was carried out to evaluate the post-blast capacity of CFRP protected reinforced concrete (RC) columns. A total of five half-scale RC columns were tested under simulated blast pressures using a shock tube testing apparatus. Three columns were strengthened with CFRP laminates of two different lay-ups, while the other two columns were left unprotected to serve as control columns. Results of this study proved that CFRP protected RC columns have substantially higher blast resistant and post-blast axial capacity than as-built columns. CFRP protection laminates containing ±45° woven laminas showed the best performance with the most ductile response.
Experimental investigation on protection methods of Slurry Infiltrated Fiber Concrete in corrosive environments
Authors: Alrubaie Mays Fouad , Ahmed Salih Shakir , Alrazaq Abbas Waleed Abd 
Published: March 2020

Abstract
Many innovations had been achieved in concrete technology since the last decades to meet the ongoing needs for new types of concrete. Slurry infiltrated fiber concrete (SIFCON) is a special type of high strength high-performance steel fiber reinforced concrete. This new type of concrete characterized by its high strength and ductility is encouragingly used in many heavy duties applications. This research is carried out to study the efficiency of using different protection methods to protect SIFCON in chloride corrosive environments. Where, corrosion inhibitor admixture, mineral admixture (local metakaolin) and epoxy protective coating were used to provide either internal or external protection for SIFCON mixes. All mixes were evaluated for more than 390 days of exposing to chloride solution. Corrosion rates, half-cell potential, concrete resistivity, and chloride concentration tests were performed. The results indicated that all SIFCON mixes showed low to moderate corrosion rates. Also it was found that using of epoxy protective coating, corrosion inhibitor and mineral admixture can reduce the rate of corrosion as compared to unprotected mixes. The cyclic wetting and drying exposure to chloride environments was more aggressive to the specimens than the partial immersion in chloride.
Behaviour of square steel anchor plate in autoclaved aerated concrete block masonry
Authors: Verba V , Kholod P 
Published: March 2020

Abstract
This research was conducted to study the mechanical behaviour of square steel anchor plate mounted in thin-bed masonry, which was made of autoclaved aerated concrete (AAC) blocks of D400 density grade. The research objectives were to determine the failure mechanism in static push-in tests and suggest the best way of structural design for anchor plate in lightweight concrete masonry, and in particular to calculate its bearing capacity. As the behaviour of small size (40×40×5 mm) anchor plate used in the research depends on the mechanical properties of the masonry units as well as on the distance to edges and joints, these properties and factors were also studied. Low strength of aerated concrete under local compression was the main reason of failure for the investigated type of anchor plate and masonry. Graphical dependencies between anchor plate displacements and applied vertical load are presented. The highest and the lowest bearing capacities of anchor plate were observed when it was mounted in the middle of the block and at the joint, respectively. The design values of the vertical concentrated load resistance of the wall, NRdc, calculated according to EN 1996-1-1, are in good agreement with experimental failure loads.
Sustainable metakaolin based pervious geopolymer concrete with recycled concrete aggregate
Authors: Frayyeh Qais J , Khalil Wasan I , Abed Haider T 
Published: March 2020

Abstract
Production of Portland cement causes many environmental problems. Whereby, about seven percent by the gross weight of CO2 emissions resulted from cement production factories. Therefore, the usage of geopolymer binder, to produce pervious concrete, instead of Portland cement considers the one solution towards conserving the environment by reducing emission of carbon dioxide. In this paper, we investigate the production of local metakaolin (MK) as a geopolymer binder to produce Pervious Geopolymer Concretes (PGC). Also, the inclusion of recycled construction materials wastes as aggregates (RA) for production of (PGCs) was studied. PGC was produced from local metakaolin (MK), sodium hydroxide (NaOH) solution, sodium silicate (Na2SiO3) solution, and recycled concrete (RC) as a volumetric partial replacement from the natural coarse aggregate (NA). All PGC specimens cured at a temperature of 50°C for five hours after 24 hours from casting and tested after 28 days. Compressive strength, total void content, splitting tensile strength, flexural strength, dry density and coefficient of water permeability for the PGCs were investigated. The results of mechanical properties were ranged from (12.23, 1.81 and 2.5) to (9.86, 1.3 and 1.95) MPa for compressive, splitting tensile and flexural strengths, respectively. The results articulate that the recycled concrete (RC) can be used as recycled coarse aggregates with a partial replacement for producing PGC with acceptable properties.
Experimental evaluation of stress-strain relations in compression for Pozzolime concrete
Authors: al-Attar T S , Abdulqader S S , Rashid R M 
Published: March 2020

Abstract
World cement demand and production are increasing. This is associated with a significant increase in the cement industry’s absolute energy use and CO2 emissions. With the increasing awareness about the environment, waste materials and by-products utilization, it has become an attractive alternative to obtain new solutions for a sustainable development. Pozzolime concrete is a promising binder alternative to Portland cement, which is forming compounds possessing cementitious properties. In this study the Pozzolime was produced via a mixture of hydrated lime and Pozzolana (Silica fume or fly ash). As a relatively new material, many engineering properties of Pozzolime concrete are still undetermined. Therefore, the modulus of elasticity and stress-strain behavior in compression have been studied experimentally. Two mixes were studied considering the compressive strength levels, 25 and 40, and for ages of 14, 28 and 56 days. The results obtained from experimental data were analyzed for stress-strain relations, compressive strength, fc, strain associated with peak compressive stress, εp, linearity of the stress-strain curve, modulus of elasticity of Pozzolime Concrete. An empirical equation is proposed for predicting stress-strain characteristics of Pozzolime concrete based on the test results by using regression analysis.
Some properties of green concrete with glass and plastic wastes
Authors: Khalil W I , Al Obeidy N F 
Published: March 2020

Abstract
This study focusses on the flexural strength, flexural toughness, thermal conductivity, and failure modes under flexural for concrete containing 15% glass powder waste as partial replacement of cement by weight and 25, 50, 75, 100% plastic waste as volumetric replacement of natural coarse aggregate at 60 days.
The results show an increase in flexural strength and thermal conductivity when 15% glass powder waste was used, while there is a significant decrease with the use of plastic waste relative to reference specimens (without wastes). It can be observed a significant increase in total flexural energy when the content of plastic waste coarse aggregate is increased.
The incorporation of plastic waste aggregate in concrete with 15% glass powder changes the failure behavior of concrete specimens from a brittle to a more ductile failure. The failure in reference concrete specimens without coarse plastic waste aggregate occurs in matrix, through coarse aggregate, and around the aggregates in interfacial transition zone (ITZ). On the other hand, in concrete containing HDPE (high density polyethylene) plastic waste aggregate with 15% glass powder, the failure occurs mainly around plastic particles.