Husam H. Hussein

Interfacial Properties of Ultrahigh-Performance Concrete and High-Strength Concrete Bridge Connections

AbstractRecently, ultra-high performance concrete (UHPC) has been utilized in highway bridge connections, where its superior strength and durability help to reduce joint cracking and enhance transverse load transfer. According to the load and resistance factor design (LRFD) bridge design procedure specified by AASHTO, the strength of the connections is dependent on the adhesion and friction between the connected materials. The objective of the present research is to identify the adhesion value between UHPC and high-strength concrete (HSC) with varying degrees of roughness. To this end, UHPC-HSC specimens were tested in direct tension according to ASTM protocols, and the maximum tensile stress at failure was obtained. Test results show that the average maximum tensile stress for the UHPC-HSC specimens with a smooth interface exceeds that determined from past research for any degree of roughness. Furthermore, the average maximum tensile stress increases with the degree of roughness. The results from the dir...

Contribution of Transverse Tie Bars to Load Transfer in Adjacent Prestressed Box-Girder Bridges with Partial Depth Shear Key

AbstractAdjacent box-girder bridges have become a popular choice as they can be constructed quickly, easily, and economically. In spite of their good performance during many years of service, one major problem has been recurrent longitudinal cracking of the grout material in the shear key. A combination of shear keys and transverse posttensioning (TPT) ties in such kind of bridges is typically used to connect the bridge girders together so that they would behave as a single integrated unit. However, information regarding the contribution of the TPT tie bars on load transfer between adjacent box girders is limited. In this study, a single-span precast prestressed concrete adjacent box-girder bridge was instrumented and monitored to study the effect of TPT tie bars on load transfer mechanism and overall bridge behavior under static and dynamic truck loads. Two sets of instruments were installed in the girders and tie bars during and after the construction of the bridge. A good correlation was achieved betwe...

Environment-Induced Behavior of Transverse Tie Bars in Adjacent Prestressed Box-Girder Bridges with Partial Depth Shear Keys

AbstractAdjacent box-girder bridges are commonly built in United States because of their fast, easy, and economical construction. They have shown good performance and service life except for freque...

Laboratory Evaluation of Ultrahigh-Performance Concrete Shear Key for Prestressed Adjacent Precast Concrete Box Girder Bridges

AbstractPrecast adjacent box girder bridges have become a preferred solution in several states due to their simple structure, economy, and ease of construction. However, longitudinal cracks often appear along the shear keys between adjacent box girders. With its superior strength and durability, ultrahigh-performance concrete (UHPC) has been used as an alternative grout material to reduce shear key cracking and enhance load transfer. The objective of the present research was to evaluate the performance of UHPC in shear keys using direct shear, direct tension, and flexural tests. Also, this study determined the effectiveness and functionality of shear reinforcement bars by applying direct shear load on specimens with shear reinforcement. In the direct shear test, a steel frame was placed around the specimens to allow the shear key to experience pure shear force. The direct shear test established the cracking threshold and ultimate shear strength of each shear key with and without shear reinforcement bars. ...