底部框架抗震墙砖房1/2比例模型拟动力试验研究

对底部两层框架抗震墙上部四层砖房 １／２比例模型进行了拟动力地震反应试验;研究了地震作用下这种结构的动力反应和破坏机理;分析了试验模型的水平承载力和破坏状态;最后对这种结构的抗震性能进行了评价。     

NUMERICAL SIMULATIONS OF A CENTERED CONDUCTING BODY ON NATURAL CONVECTION AND HEAT TRANSFER IN AN ENCLOSURE

1.INTRODUCTIONA heat-conducting body is located somewherewithinthe enclosure,thereby affecting the naturalconvection flowand heat transfer.Soit is veryi m-portant in theory and used widely in many engi-neering systems.For example in a metal castingprocess,a solid may be placedinthe mold to forma holeinthe casting,another examplein electronicpackages with windows or walls.Natural convection and heat transfer of a cen-tered conducting body in an enclosure are complexproblems in the fluid me…     

Compressive evaluation of mansory bricks produced with industrial byproduct aggregates

This study evaluates the effect upon the compressive strength of ceramic masonry bricks when industrial byproducts known as soot are added. The research includes an analysis of the granulometric properties of the constituent components, performed manually with ASTM C136-01 screens to determine particle size using apertures sized from large to small; an analysis by XRD of the mineralogical phases present; a compressive strength analysis performed using standard compression testing machinery; and a water absorption measurement calculated according to Colombian Technical Standard: 4017:2015—Methods for the Sampling and Testing of Masonry Elements and other Clay Products. Five trials were performed using different mixtures of clay and soot, at substitution rates of 20%, 30%, 40%, 50%, and 60%. These mixtures were prepared under identical conditions in order to ensure validity of the resulting comparisons. The results showed that bricks with 20%, 30%, 40%, and 50% added soot demonstrated superior structural strength compared to conventional units. Bricks incorporating 60% soot, however, were found to have lower strength and high porosity.     

短肢砌体剪力墙的偏心受压承载力分析

应用ANSYS结构有限元分析软件,选择三维八节点的混凝土单元Solid65模拟灌孔砌块砌体、杆单元Link8模拟钢筋,针对竖向偏心荷载作用下的配筋砌块短肢砌体剪力墙进行了三维非线性有限元分析,研究了该类墙体的破坏形态、承载与变形能力,并将模拟结果与试验值进行了对比,验证了有限元分析方法的可行性。在得到可靠验证的基础上,进行了扩大参数分析,研究了不同偏心距对承载力的影响。     

砌体结构验收亟须解决的几个问题

本文针对目前困扰砌体结构验收中涉及实体工程质量验收(检测)的几个问题进行分析,对如何解决这些问题提出一些建议.     

沈阳市采煤沉陷区受损民居的修复与加固

通过沈阳市采煤沉陷区的加固方案设计,对在设计过程中涉及到的破坏特点、修复原则、加固方法等问题进行了相应的探讨.     

轻质混凝土砌块砌体受压性能试验研究

对轻质混凝土小型空心砌块砌体进行了抗压性能试验,主要研究不同砂浆强度等级对其抗压性能的影响,分析了砌体的破坏特征、抗压强度和应力与应变之间的关系。研究结果表明:轻质混凝土小型空心砌块砌体的抗压性能和普通混凝土砌块砌体的抗压性能基本相似,极限破坏状态为砌体被贯通裂缝分隔成小立柱后破坏。通过对试验数据的整理分析,给出了砌块砌体抗压强度平均值的计算公式和上升阶段的应力-应变关系式。     

钢框架内填预制钢筋混凝土剪力墙试验研究

为改进钢框架内填预制钢筋混凝土剪力墙的抗震性能,将耳板装置引入钢框架与内填墙的连接中.通过2个2层单跨钢框架内填预制钢筋混凝土剪力墙1/3模型试件的循环荷载试验,考察耳板连接装置的可靠性和内填墙裂缝的开展与结构变形能力,分析结构的破坏机理、滞回性能、刚度退化、变形及延性等,并对钢框架内填预制混凝土剪力墙体系与现浇混凝土剪力墙体系和带竖缝混凝土剪力墙体系进行对比.研究结果表明:抗剪连接件(U形筋)在梁柱节点上下耳板的帮助下未发生破坏,耳板连接装置具有可靠的工作性能;合理设计的钢框架内填预制钢筋混凝土剪力墙结构具有良好的延性.     

蒸压粉煤灰砖砌体抗压试验研究

通过对蒸压粉煤灰砖和烧结粘土砖砌体的抗压试验以及专用砂浆的抗压试验,验证了＂销栓＂作用对提高砌体抗压强度的重要性,并绘制出应力应变曲线,计算出的蒸压粉煤灰砖砌体弹性模量是规范值的2.09～2.42倍,因此砌体是偏安全的。     

Reinforcement load and deformation mode of geosynthetic-reinforced soil walls subject to seismic loading during service life

A Finite Element procedure was used to investigate the reinforcement load and the deformation mode for geosynthetic-reinforced soil (GRS) walls subject to seismic loading during their service life, focusing on those with marginal backfill soils. Marginal backfill soils are hereby defined as filled materials containing cohesive fines with plasticity index (PI) >6, which may exhibit substantial creep under constant static loading before subjected to earthquake. It was found that under strong seismic loading reinforced soil walls with marginal backfills exhibited a distinctive “two-wedge” deformation mode. The surface of maximum reinforcement load was the combined effect of the internal potential failure surface and the outer surface that extended into the retained earth. In the range investigated, which is believed to cover general backfill soils and geosynthetic reinforcements, the creep rates of soils and reinforcements had small influence on the reinforcement load and the “two-wedge” deformation mode, but reinforcement stiffness played a critical role on these two responses of GRS walls. It was also found that the “two-wedge” deformation mode could be restricted if sufficiently long reinforcement was used. The study shows that it is rational to investigate the reinforcement load of reinforced soil walls subject to seismic loading without considering the previous long-term creep.