砖混结构房屋现浇楼板斜裂缝的有限元分析

砖混结构在我国民用住宅中普遍使用,但砖混结构房屋中出现的现浇楼板斜裂缝问题也引起各方的关注。结合工程实例,在假定结构处于弹性工作范围内,混凝土不开裂的前提下,对现浇楼板的斜裂缝进行了有限元分析,并提出一些预防裂缝的建议。     

混凝土旧房改造应有自己的规范──碳化混凝土结构设计规范

混凝土旧房改造应有自己的规范──碳化混凝土结构设计规范朱伯龙，刘祖华（同济大学，上海２０００９２）众所周知：现行混凝土规范是以试验为基础制定的，而混凝土试验又全是新打的混凝土，即新鲜混凝土。无庸置疑，这对设计新建混凝土房屋当然是完全正确的，但另一方面...     

Experimental Study of Two-Alpha Emission from High-Lying Excited States of 17,18Ne

The experiments of two-alpha emission from 17,18Ne excited levels were performed at the HIRFL-RIBLL facility of the Institute of Modern Physics, Lanzhou. The beams of 17Ne at the energy of 49.9 MeV/u and 18Ne at 51.8 MeV/u bombarded a 197Au target to populate excited states of 17,18Ne via Coulomb excitation. Complete kinematics measurements were achieved by the detectors of a silicon strip and CsI+PIN array. The experimental results combined with simple MC simulations show the characteristic of sequential two-alpha emission via 14O excited states for 18Ne. The results of two-alpha emission from 17Ne are preliminary and need further analyses.     

Breakup Effect of Weakly Bound Projectile on the Barrier Distribution Around Coulomb Barrier

The excitation function of quasi-elastic (QEL) scattering at a backward angle has been measured for 9 Be+ 208 Pb. The barrier distribution was extracted by means of the first derivative of the measured excitation function and calculated with the coupled-channel model. The present work shows that the experimental barrier distribution extracted from QEL scattering is shifted to the low energy side by 1.5 MeV as compared with the theoretical one. This energy discrepancy indicates that breakup is important in the colliding processes of the weakly bound nucleus system.     

化学锚栓裂缝反复开合试验研究

化学锚栓已广泛应用于各类工程的加固和改造,但化学锚栓性能与混凝土基材开裂状况之间的关系尚待深入研究.通过化学锚栓裂缝反复开合性能试验,研究混凝土基材开裂状况对化学锚栓性能的影响.结果表明:在混凝土基材裂缝反复开合时,化学锚栓的位移变化量很小,满足使用要求.另外,试验还对化学锚栓三种主要的破坏形态进行了观察,通过计算抗拉承载力变异系数及锚固系数,得到了化学锚栓在开裂混凝土中的剩余抗拉承载力.     

不锈钢材料扩张网拉伸试验研究

不锈钢扩张网材料,具有良好的耐久性和耐腐蚀性,目前已经广泛应用于建筑工程的墙面结构、围墙拦网、隔离栏栅等领域。文中将针对某实际工程中具体的扩张网形式,对不锈钢扩张网进行拉伸试验,通过观察试验现象,分析试验数据等工作,研究其承载能力和破坏机理。     

钢筋混凝土框架结构的抗震加固

简要介绍了某带夹层钢筋混凝土框架结构加固改造的抗震评价,通过改变结构体系,使得加固后结构能满足规范的抗震要求,为同类结构体系的改造加固提供了参考。     

混凝土楼板及地砖组合体温度效应分析

用ANSYS8.1结构分析有限元软件,建立了混凝土楼板及地砖组合体的有限元二维模型,并考虑不同长度的影响,计算在夏季和冬季正常室内开启空调温度工况下楼板(包括上层地砖)的整体温度场,并分析计算了相应的温度应力分布,为以后具体构件的温度设计提供了参考。