In the past few years, some experimental investigations have been conducted to verify seismic behaviour of fiber reinforced polymer reinforced concrete (FRP-RC) beam-column joints. Those researches were mainly focused on exterior beam-column joints without lateral beams. However, lateral beams, commonly exist in buildings, can significantly improve seismic performance of the joints. Moreover, the way the longitudinal beam bars are anchored in the joint, either using headed-end or bent bars, was not adequately addressed. This study aims to fill these gaps and investigate the shear capacity of FRP-RC exterior beam-column joints confined with lateral beams, and the effect of beam reinforcement anchorage on their seismic behaviour. Six full-scale exterior beam-column joints were constructed and tested to failure under reversal cyclic loading. Test results showed that the presence of lateral beams significantly increased the shear capacity of the joints. Moreover, replacing bent bars with headed-end bars resulted in more ductile behaviour of the joints.

The Icy Springs Bridge in Coalville, Utah carries 2nd South Street over the Weber River west of Interstate 80. The bridge is owned by Coalville City and was originally constructed in 1965 as a single-span 51-foot long bridge using prestressed concrete double-tee girders. In the fall of 2013 the original bridge was replaced with a new 80-foot long single span bridge using prestressed concrete decked bulb-tee girders. The original girders were salvaged and transported to the Systems, Materials, and Structural Health Lab (SMASH Lab) where a series of tests were performed to determine the total losses in the prestressing of the strands, the flexural and shear capacities of the girders, and the punching shear capacity of the reinforced concrete deck. The results of these tests were compared to the values calculated using methods outlined in the 2012 American Association of State Highway and Transportation Officials Load and Resistance Factor Design (AASHTO LRFD) Bridge Design Specifications, the current bridge design code used by most departments of transportation, and a finite element model using the computer program ANSYS. For the shear and punching shear test results, the AASHTO LRFD Bridge Design Specifications was conservative and was able to predict the type of failure that occurred. However, the tested flexural results were below the calculated flexural capacities using the AASHTO LRFD Bridge Design Specifications. A finite element model was created and calibrated to the test results for the various loading and support conditions. The actual tested material properties were compared to the material properties used in the finite element analyses to determine the difference between the actual girders and the theoretical models. Funding for this project was provided by the Utah Transportation Center.

The ultimate shear capacity of prestressed concrete beams is difficult to predict accurately, especially after being in service for an extended period of time. The Utah Department of Transportation asked researchers at Utah State University to experimentally determine the existing shear capacity of 41-year-old prestressed, decommissioned concrete bridge girders and then provide recommendations on how to increase that ultimate shear capacity. This thesis presents the research findings that relate to the existing shear capacity of the prestressed concrete girders. Eight AASHTO Type II bridge girders were tested up to failure by applying external loads near the supports to determine their ultimate shear capacities. The measured results were then compared to calculated values obtained using the AASHTO LRFD bridge design code, and the ACI 318-08 design code. Prestress losses were also measured by means of a cracking test and then compared to values calculated according to the AASHTO prestress loss equations. Both the ultimate shear capacities and the residual prestress forces were used to evaluate the girders after being in service for more than 40 years.

Use of composite steel construction with precast hollow core slabs is now popular in the UK, but the present knowledge in shear capacity of the headed shear studs for this type of composite construction is very limited. Currently, all the information is based on the results obtained from experimental push-off tests. A finite element model to simulate the behaviour of headed stud shear connection in composite beam with precast hollow core slabs is described. The model is based on finite element method and takes into account the linear and non-linear behaviour of all the materials. The model has been validated against the test results, for which the accuracy of the model used is demonstrated. Parametric studies showing the effect of the change in transverse gap size, transverse reinforcement diameter and in-situ concrete strength on the shear connection capacity are presented.

yes / Twenty two reinforced concrete continuous deep beams with openings and two companion solid deep beams were tested to failure. The main variables investigated were the configuration of web reinforcement around openings, location of openings, and shear span-to-overall depth ratio. The influence of web reinforcement on controlling diagonal crack width and load capacity of continuous deep beams with openings was significantly dependent on the location of openings. The development of diagonal crack width and load capacity of beams having openings within exterior shear spans were insensitive to the configuration of web reinforcement. However, for beams having openings within interior shear spans, inclined web reinforcement was the most effective type for controlling diagonal crack width and increasing load capacity. It has also observed that higher load and shear capacities were exhibited by beams with web reinforcement above and below openings than those with web reinforcement only above openings. The shear capacity at failed shear span of continuous beams tested is overestimated using Kong et al’s formula developed for simple deep beams with openings.

Yes / This paper presents an experimental study on an innovative composite floor system that can be demounted and deconstructed. In this system, the composite slab, formed with profiled metal decking, was connected to a steel beam via demountable shear connectors. A full-scale demountable composite floor system specimen was tested to ultimate load bearing capacity and compared with a similar non-demountable composite floor system specimen using conventional welded headed stud connectors. The experimental results and observations showed that the structural behaviour and load bearing capacity of both composite floor systems are very similar. However, the composite floor system with demountable shear connectors could be deconstructed after testing and the composite slab could be easily detached from the steel beam. The comparison and analysis presented in this paper indicated that the simple design methods currently provided in the Eurocode 4 for the welded shear connections could be used to assess the ultimate moment capacity of demountable composite floor systems.

yes / This paper presents an experimental study on shear strength, stiffness and ductility of demountable shear connectors in metal decking composite slabs through push-off tests. Twelve full-scale push-off tests were carried out using different concrete strength, number of connectors and different connector diameter. The experimental results showed that the demountable shear connectors in metal decking composite slabs have similar shear capacity and behaviour as welded shear studs and fulfilled the minimum ductility requirement of 6mm required by Eurocode 4. The shear capacity was compared against the prediction methods used for the welded shear connections given in Eurocode 4, AISC 360-10, ACI 318-08 and method used for bolted connection in Eurocode 3. It was found that the AISC 360-10 method overestimated the shear capacity while the ACI 318-08 method underestimated the shear capacity of specimens with single shear connector per trough. The Eurocodes method was found to provide a safe prediction for specimens with single and pair demountable connectors per trough. In addition, prediction methods given in both AISC 360-10 and ACI 318-08 for welded shear studs overestimated the shear capacity of specimens with 22 mm diameter demountable connectors that failed in concrete crushing. / PhD work from EPSRC studentship

No abstract is provided. / Thesis / Master of Engineering (MEngr) / Scope and contents: In this report, a method for calculating the longitudinal shear capacity of the slab of simply-supported steel-concrete composite beams is presented. The method is based on analysing the stresses at failure of the concrete elements located at the slab shear surface. In this analysis, the slab width and the shear span are found to be two main parameters that have been neglected in the empirical solutions previously adopted.

yes / The validity of the modification factor specified in the ACI 318-11 shear provision for concrete members to account for the reduced frictional properties along crack interfaces is examined using a comprehensive database comprised of 1716 normalweight concrete (NWC) beam specimens, 73 all-lightweight concrete (ALWC) beam specimens, and 54 sand-lightweight concrete (SLWC) beam specimens without shear reinforcement. Comparisons of measured and predicted shear capacities of concrete beams in the database show that ACI 318-11 provisions for shear-transfer capacity of concrete are less conservative for lightweight concrete (LWC) beams than NWC beams. A rational approach based on the upper-bound theorem of concrete plasticity has been developed to assess the reduced aggregate interlock along the crack interfaces and predict the shear-transfer capacity of concrete. A simplified model for the modification factor is then proposed as a function of the compressive strength and dry density of concrete and maximum aggregate size on the basis of analytical parametric studies on the ratios of shear-transfer capacity of LWC to that of the companion NWC. The proposed modification factor decreases with the decrease in the dry density of concrete, gives closer predictions to experimental results than does the ACI 318-11 shear provision and, overall, improves the safety of shear capacity of LWC beams.

Yes / A novel prestressed precast reinforced concrete (RC) beam-column joint, composed of prestressed tendons, stiffened steel sleeves, and high-strength bolts, having improved self-centring ability and assembly efficiency is proposed in this paper. Four prestressed precast RC joints assembled by steel sleeves and one cast-in-place RC joint were tested under cyclic loading to investigate the seismic response of the proposed joint. The main parameters studied are the axial compression ratio of columns, stirrup ratio in the core area of the proposed joint and effective prestress of tendons. The energy dissipation capacity, bearing capacity, and self-centring ability of the prestressed precast RC beam-column joints assembled by steel sleeves are higher than those measured for the cast-in-place RC joint. For the prestressed precast RC joints assembled by steel sleeves, both yield and ultimate displacements increase with the increase of the axial compression ratio, stirrup ratio and effective prestress, but the ductility decreases with the increase of the axial compression ratio and effective prestress. The increasing of axial compression ratio can lead to an increase in the energy dissipation capacity, shear capacity and residual displacement. Finally, formulae to predict the shear capacity of prestressed precast RC joint assembled by steel sleeves are proposed, being in good agreement with the experimental results. / The authors would like to thank the financial support provided by the Natural Science Foundation of Jiangsu Province, China (BK20201436), the Open Foundation of Jiangsu Province Engineering Research Center of Prefabricated Building and Intelligent Construction (2021), the Blue Project Youth Academic Leader of Colleges and Universities in Jiangsu Province (2020) and the Postgraduate Research & Practice Innovation Program of Jiangsu Province, China (KYCX21_3225).