The load-deformation response of R/C membrane elements (panels) subjected to reversed cyclic shear shows that the orientation of the steel bars with respect to the principal coordinate of the applied stresses has a strong effect on the "pinched shape" of the post-yield hysteretic loops. When the steel bars in a panel are oriented in the coordinate of the applied principal stresses, there is no "pinching effect," and the panel exhibits ductile behavior and high capacity of energy dissipation. Whereas, when the steel bars are oriented at an angle of 45 degrees to the applied principal stresses, severe pinching effect is observed and the panel becomes more brittle. This paper presents concisely a rational theory, called the Cyclic Softened Membrane Model (CSMM). This new rational theory is capable of predicting the entire history of the hysteretic loops (pre-and post-yeild); can explain the mechanism behind the "pinching effect"; and can elucidate the failure mechanism that causes the deteriorations of reinforced concrete structures under cyclic loading.

In most curricula, students have numerous opportunities to work as part of a team, but they are seldom instructed on how to function as part of a team, a valuable skill in the corporate environment. As part of a larger initiative to develop five fundamental skills, Tufts University's School of Engineering has implemented a program to introduce teamwork skills to all engineering students. This program is designed to develop good habits for functioning as part of a team. In context of the work being presented, the team working skills were introduced into a sophomore level civil entgineering materials course (including concrete, of course!). Students were given two lectures followed by laboratory exercises to emphasize the teamwork concept of defining and working towards a common goal and not being so driven by the task. The students then practiced their skills throughout the course by functioning as teams in all their laboratory exercises and report writing. Through roper functioning teams, cooperative learning is promoted, and students learn the material beeter and more efficiently. Team performances were periodically assessed. Overviews of the School of Engineering's five fundamental skills program and teamwork initiative are presented. Outcomes from the teamwork program incorporated into the civil engineering materials course were assessed at several stages uring the class and are reported.

High-Performance Fiber Reinforced Cocndrete (HPFRC) exhibits features particularly desirable for increasing earthquake resistance such as high tensile strength and ductility. However, since HPFRC is substantially different from conventional materials, using existing design and construction procedures does not lead to the most cost-effective solutions. To address this issue, this paper presents a way of selectively using Slurry Infiltrated Mat Concrete (SIMCON), Slurry Infiltraded Fiber Concrete (SIFCON) and high Strength Lightweight Aggregate Fiber kReinforced Concrete (HS_LWA FRC) to construct is to improve cost effectiveness by simplifying both construction and postearthquake repair, increasing the construction speed, lowering seismically induced forces and increasing overall seismic resistance. This is achieved by fuses with cast in place HS-LWA FRC. First, the paper presents experimentally evaluated behavior of HPCF members. Next the seismic response of a four story HPCF building is investigated analytically and compared to that of a seismically designed R.C. frame. HPCF reached an overall good seismic response. As compared to the reference building, it exhibited slower strength and stiffness degradation, lower top displacements and story drifts. Overall building damage was lower for the HPCF building, and even under 33% higher seismic excitations the HPCF building had higher seismic resistance than the reference R. C. Building.

Fracture mechanics concepts were first applied to concrete in 1959, and since then several thousand papers have been published on this topic. Professor Shah himself has contributed many papers in this area, dating back to 1971. The first attemps at utilizing fracture mechanics in concrete research dealt with linear elastic fracture mechanics in concrete research dealt with linear elastic fracture mechanics. However, it soon became apparent that this was insufficient to characterize a heterogeneous, non-linear elastic material such as concrete. Thus, a variety of non-linear fracture mechanics models were developed to try to better describe the fracture and failure of concrete. Unfortunately, despite a great deal of researh, both theoretical and experimental, fracture mechanics concepts are still seldom used in the design of concrete structures, particularlay in North America. For instance, they are not even mentioned in the current ACI 318 Building kCode Requirements for Structural Concrete, or in the kCanadian CSA Standard A23.3 Design of Concrete Structures. It is the purpose of this paper to review briefly the current position of fracture mechanics in concrete applications, and then to look to possible future developments.

The service performance of repaired structures depends mainly on the mechanical properties of the substrate and repair materials and the mechanical behavior of the interface between them. However, in most studies in the literature, on ly bond strength is used to evaluate the repair and the deformation behavior of the interface is usually neglected. In this study, three slabs were cast using conventional concrete as a substrate. The substrate surface was roughened with jackhammers. A layer of 50-60 mm repair materials were cast by shotcreting or by hand. The test specimens were cored or cut to the required size. Direct tensile and compression tests were performed to evaluate the bond strength and mechanical behavior of the interface between substrate and repair materials. The test results indicate that the bond strenght was affected by the mix proportions and independent on the casting method and the inclusion of steel fibers. However the casting methods had a strong influence on the mechanical behavior of the interface between substrate and repair material.