【正文】 residual mortar volume fraction of Although by suitable adjustment of the cement content and watercement ratio (w/c) of mixtures involving RCA, concrete with higher pressive strength than the concrete from which the RCA originated has been produced,3 such adjustments have not resulted in parable RCAconcrete possessing superior elastic modulus, bond strength, or stressstrain characteristics to similar grade conventional ,4 Consequently, it has been reported that structural members made from RCAconcrete experience larger deflection, exhibit wider cracks and smaller crack spacing, and have relatively lower flexural strength pared to the panion conventional concrete This kind of variability constitutes a drawback and discourages its use because it creates uncertainty with respect to the serviceability and longterm performance of RCAconcrete structures.To overe this problem, in a separate investigation,described in detail elsewhere, the authors developed a new mixture proportioning method for RCAconcrete called the equivalent mortar volume (EMV) In this method, RCA is treated as a twophase posite material prising residual mortar and original natural aggregate。 英文原文2Seismic Behavior and Capacity/Demand Analyses of a SimplySupported MultiSpan Precast BridgeNasim Shatarat and Adel Assaf International Journal of Applied Science, Engineering and Technology 5:4 2009ACOMMONLY used type of bridges in Washington State (WA) in the 1950’s and 1960’s is MultiSpanSimplySupported (MSSS) precast system. This system was proven at the time to be easy to be designed and to be constructed. The designers used a predesigned tabulated set of bridge ponents, where the superstructure and the substructure ponents are selected based on certain global characteristics and dimensions of the bridge such as, height of the columns, roadway width, bent skewness and span length. The predesigned bridges always hold the same assumptions in terms of material strength. Then, modification to f