(1)Systems of reinforcing concrete for strength and ductility, (2) serviceability of concrete structures

1)强度和延性的钢筋混凝土系统混凝土中的钢筋只有在正锚定在混凝土上时才能抵抗等于其全部屈服强度的力。传统的马镫和十字马镫依靠钩子或弯曲来锚定。然而，在对钩或弯道附近钢筋的屈服强度有要求的地方，试验通常会在界面处出现混凝土的破碎或分裂，并伴有锚固滑移。钢筋系统的开发用于混凝土，以代替传统的箍筋和交叉。新系统的基本组成部分是一个螺柱，两端各有一个锚头，能够发挥螺柱的全部屈服强度而不打滑。这种锚固质量使螺柱在提供强度和延展性（对抗震结构至关重要）方面比传统箍筋更有效。螺柱的应用实例有：在楼板、柱、墙和桥墩上的交叉筋、深（或短）梁和梁上的纵向筋以及在轴承和预应力筋末端的抗劈裂筋。(2)混凝土结构的适用性本项目旨在发展计算温度、混凝土徐变和收缩引起的应力和应变以及预应力钢筋松弛的可靠技术，并相应地设计最小钢筋及其细部，以确保令人满意的使用寿命和耐久性。这项工作包括考虑材料和几何非线性，由混凝土开裂、钢筋屈服、轴向力的存在和使用无粘结或外部预应力筋引起的非线性。分析考虑了混凝土构件在徐变、收缩和松弛发生后，在荷载作用下的变形直至破坏。

1) Systems of Reinforcing Concrete for Strength and DuctilityA steel reinforcing bar in concrete can resist a force equal to its full yield strength only when it is positively anchored to the concrete. Conventional stirrups and crossties rely on hooks or bends for anchorage. However, where there is demand for the yield strength of the bar adjacent to a hook or a bend, experiments typically exhibit crushing or splitting of the concrete at the interface, accompanied by anchorage slip. Systems of steel reinforcement are developed for use in concrete in lieu of conventional stirrups and crossties. The basic component of the new systems is a stud with an anchor head at each end, capable of developing the full yield strength of the stud without slip. This anchorage quality makes the studs more efficient than conventional stirrups in providing strength and particularly ductility (essential for earthquake-resistant structures). Examples of applications of studs are: punching shear reinforcement in slabs, crossties in columns, walls and bridge piers, longitudinal bars in deep (or short) beams and corbels, and anti-splitting reinforcement at bearings and ends of prestressing tendons.(2) Serviceability of Concrete StructuresThis project aims at development of robust techniques of computing stresses and strains due to temperature, creep and shrinkage of concrete and relaxation of prestressing reinforcement and, accordingly, design the minimum reinforcement and its detailing to ensure satisfactory service life and durability. The work involves considering material and geometric nonlinearities, caused by cracking of concrete, yielding of reinforcement, presence of axial forces and use of unbonded or external prestressing tendons. The analysis considers the deformation up to failure of concrete members subjected to increasing load introduced after occurrance of creep, shrinkage and relaxation.