No / Much of the environmental impact of buildings is associated with consumption of resources and generation of waste. The construction industry in Europe consumes over 70,000 million tonnes of a wide range of materials each year, and generates over 250 million tonnes of waste. Reducing waste is a priority for all the European Governments. Composite flooring formed by connecting the concrete slabs to the supporting steel beams has been widely used for many years throughout the world. The use of composite action between steel and concrete is well established as a cost-effective arrangement for floor systems in multi-storey steel frame building structures. Composite action between steel beams and concrete slabs through the use of shear connectors are responsible for a considerable increases in the load-bearing capacity and stiffness of the steel beams, which when utilised in design, can result in significant savings in steel weight and construction cost. However, shear connectors are welded through the steel decking and cast into the concrete; this made deconstruction and reuse of the steel components almost impossible. A demountable shear connector is developed and tested to assess its potential and suitability in term of replacing the welded through headed shear studs. Test results shown that these shear connectors can be easily demounted after test and have a similar capacity and behaviour of the welded shear connectors. In addition, test results showed that the new demountable shear connectors process high ductility in comparison with the welded shear connectors.

Full-depth precast panels are used in concrete bridges to provide several benefits such as faster construction, lower cost and reduced constructional hazard. However, one construction drawback is that connectors are required to transmit horizontal shear across the interface between the girder and deck. Shear connector performance is characterized by a series of experiments performed on part of a bridge system that mimics a full-depth precast deck on concrete girder with a pocket-connector-haunch system. Following initial breakaway of the adhesive bond within the haunch region, the specimens slide with frictional resistance provided by the clamping force of the anchor bolt. This leads to bolt yield with an observed sliding friction coefficient of 0.8 (+/- 20%) with lower values occurring at higher displacements. It is concluded that for a viable connector system to be developed a key feature is to have sufficient stirrups in the neighborhood of the anchor bolt to form a non-contact splice and to ensure the high pull-out force can be sustained without leading to premature beam failure. The successful implementation of a full-depth precast deck-panel system requires the use of a viable design methodology that properly accounts for system behavior. The design of a deck-haunch-girder system uses a truss modeling approach to design for the shear forces created by service loading. The truss model approach is considered more suitable for a concrete member due to the premise that the member will be substantially cracked at an ultimate limit state and that traditional beam theory does not account for the decreased ability of shear stresses to transfer across open cracks. Experimental results from Chapter II, such as the friction coefficient mu, are used along with a previously developed crack angle model to layout the geometry of the truss within a deck-panel span. Design solutions are presented utilizing the Rock Creek Bridge in Parker County, Texas as an example structure.

The purpose of this study is to evaluate the performance of the 5/16 in. diameter Elco Grade 8 standoff screw as a mechanical shear connector in composite joists. Standoff screws are being investigated as an alternative to welded shear studs in short span composite joists. The data and results obtained from 106 pushout tests performed on the Elco Grade 8 standoff screw are presented. The test parameters include: standoff screw height, quantity of standoff screws per deck rib, standoff screw position, slab depth, base angle thickness, deck type, and amount of transverse reinforcement. The test results from this study are compared to those obtained in previous research performed by Hankins (1994), and the applicability of Hankins' predictive equation for the shear strength of the Elco Grade 8 standoff screw is investigated. The influences of various test parameters on the shear strength of the standoff screw are evaluated and the effects of grouping the standoff screws in the deck ribs are examined. The performance of the standoff screw in solid slab applications is also investigated. Predictive equations for the shear strength of the Elco Grade 8 standoff screw, based on screw-related failure modes, concrete rib failures, and longitudinal splitting of solid concrete slabs, are presented. / Master of Science

No / This paper presents a numerical investigation into the behaviour of headed shear stud in composite beams with profiled metal decking. A three-dimensional finite element model was developed using general purpose finite element program ABAQUS to study the behaviour of through-deck welded shear stud in the composite slabs with trapezoidal deck ribs oriented perpendicular to the beam. Both static and dynamic procedures were investigated using Drucker Prager model and Concrete Damaged Plasticity model respectively. In the dynamic procedure using ABAQUS/Explicit, the push test specimens were loaded slowly to eliminate significant inertia effects to obtain a static solution. The capacity of shear connector, load-slip behaviour and failure modes were predicted and validated against experimental results. The delamination of the profiled decking from concrete slab was captured in the numerical analysis which was observed in the experiments. ABAQUS/Explicit was found to be particularly suitable for modelling post-failure behaviour and the contact interaction between profiled decking and concrete slabs. It is concluded that this model represents the true behaviour of the headed shear stud in composite beams with profiled decking in terms of the shear connection capacity, load-slip behaviour and failure modes.

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The purpose of this study is to further evaluate the performance of the 5/16 in. diameter Elco Grade 8 standoff screw as a mechanical shear connector in composite joists. Standoff screws are being investigated as viable an alternative to welded shear studs in short span composite joists. The data and results obtained from 59 pushout tests performed on the 5/16 in. diameter Elco Grade 8 standoff screw are presented. The test parameters investigated in this study include: standoff screw height, quantity of standoff screws per deck rib, standoff screw position, slab depth, base angle thickness, deck type, and amount of transverse reinforcement. Test results gathered in this study are used in conjunction with selected test data from research performed by Alander (1998). This combined test data is used in determining the validity of existing predictive equations for the shear strength of the 5/16 in. diameter Elco Grade 8 standoff screw. The influence of various independent variables on shear strength is investigated for all screw densities tested. The performance of the 5/16 in. diameter Elco Grade 8 standoff screw in solid slab applications is also investigated. Proposed predictive equations for the shear strength of the 5/16 in. diameter Elco Grade 8 standoff screw based on screw-related failure modes, concrete cone failures and longitudinal splitting, are presented. / Master of Science

The full-width, full-depth precast panel system is very convenient for rehabilitation of deteriorated decks as well as for new bridge construction. The horizontal shear strength at the interface between the two interconnected elements is of primary importance in order to provide composite action. The strength of the bond between the two precast members should be high enough to prevent any progressive slip from taking place. Flexural strength, shear strength and deflection characteristics all depend on the satisfactory performance of the interface to provide composite action. However, the case when both of the interconnected elements are precast members bonded by means of grout, is not currently addressed by ACI or AASHTO. This is the main impetus for this project. A total of 36 push-off tests were performed to develop a method for quantifying horizontal shear strength and to recommend the best practice for the system. Test parameters included different haunch heights, different grout types, different amount and different type of shear connectors. Two equations, for uncracked and cracked concrete interfaces, are proposed to be used in horizontal shear design when the precast panels are used. Predictive equations are compared with available methods for the horizontal shear strength of the precast panel system. Conclusions and recommendations for the optimum system are made. / Master of Science

This thesis summarizes the results of an experimental investigation involving the testing of push-out specimens with channel shear connectors. The test program involved the testing of 78 push-out specimens and was aimed at the development of new equations for channel shear connectors embedded in solid concrete slabs and slabs with wide ribbed metal deck oriented parallel to the beam. <p>The test specimens were designed to study the effect of a number of parameters on the shear capacity of channel shear connectors. Six series of push-out specimens were tested in two phases. The primary difference between the two phases was the height of the channel connector. Other test parameters included the compressive strength of concrete, the length and the web thickness of the channel. <p>Three different types of failure mechanisms were observed. In specimens with higher strength concrete, failure was caused by the fracture of the channel near the fillet with the channel web acting like a cantilever beam. Crushing-splitting of concrete was the observed mode of failure in specimens with solid slabs when lower strength concrete was used. In most of the specimens with metal deck slabs, a concrete shear plane type of failure was observed. In the specimens involving this type of failure, the channel connector remained intact and the concrete contained within the flute in front of channel web sheared off along the interface. <p>The load carrying capacity of a channel connector increased almost linearly with the increase in channel length. On average, the increase was about 39% when the channel length was increased from 50 mm to 100 mm. There was a further increase of 24% when the channel length was increased from 100 mm to 150 mm. The influence of web thickness of channel connector was significant when the failure occurred due to channel web fracture but was minimal for a concrete crushing-splitting type of failure. <p>The specimens with solid concrete slabs carried higher load compared to those with metal deck slabs. The increase in load capacity was 33% for specimens with 150 mm long channels but only 12% for those with 50 mm long channel connectors. <p>This investigation resulted in the development of a new equation for predicting the shear strength of channel connectors embedded in solid concrete slabs. The proposed equation provides much better correlation to test results than those obtained using the current CSA equation. <p>The results of specimens with metal deck slabs were used to develop a new equation for predicting the shear capacity of channel connectors embedded in slabs with metal deck oriented parallel to the beam. The values predicted by the proposed equation were in good agreement with the observed test values.

This thesis summarizes the results of an experimental investigation involving the testing of push-out specimens with channel shear connectors. The test program involved the testing of 78 push-out specimens and was aimed at the development of new equations for channel shear connectors embedded in solid concrete slabs and slabs with wide ribbed metal deck oriented parallel to the beam. <p>The test specimens were designed to study the effect of a number of parameters on the shear capacity of channel shear connectors. Six series of push-out specimens were tested in two phases. The primary difference between the two phases was the height of the channel connector. Other test parameters included the compressive strength of concrete, the length and the web thickness of the channel. <p>Three different types of failure mechanisms were observed. In specimens with higher strength concrete, failure was caused by the fracture of the channel near the fillet with the channel web acting like a cantilever beam. Crushing-splitting of concrete was the observed mode of failure in specimens with solid slabs when lower strength concrete was used. In most of the specimens with metal deck slabs, a concrete shear plane type of failure was observed. In the specimens involving this type of failure, the channel connector remained intact and the concrete contained within the flute in front of channel web sheared off along the interface. <p>The load carrying capacity of a channel connector increased almost linearly with the increase in channel length. On average, the increase was about 39% when the channel length was increased from 50 mm to 100 mm. There was a further increase of 24% when the channel length was increased from 100 mm to 150 mm. The influence of web thickness of channel connector was significant when the failure occurred due to channel web fracture but was minimal for a concrete crushing-splitting type of failure. <p>The specimens with solid concrete slabs carried higher load compared to those with metal deck slabs. The increase in load capacity was 33% for specimens with 150 mm long channels but only 12% for those with 50 mm long channel connectors. <p>This investigation resulted in the development of a new equation for predicting the shear strength of channel connectors embedded in solid concrete slabs. The proposed equation provides much better correlation to test results than those obtained using the current CSA equation. <p>The results of specimens with metal deck slabs were used to develop a new equation for predicting the shear capacity of channel connectors embedded in slabs with metal deck oriented parallel to the beam. The values predicted by the proposed equation were in good agreement with the observed test values.