基于裂缝宽度的现有构件承载力评估概述

基于对锈蚀钢筋混凝土梁破坏特征的分析,探讨了影响锈蚀构件承载能力的因素,并对现有服役钢筋混凝土结构构件承载能力进行了详细的论述,为混凝土结构耐久性评估和可靠度鉴定提供科学的依据。     

黄土场地正方形布桩刚性桩复合地基承载力研究

依托黄土场地某产品仓工程,对正方形布桩条件下刚性桩复合地基承载力进行了现场试验研究,基于三个载荷点的静载试验,确定了厚层黄土场地正方形布桩条件下刚性桩复合地基承载力,为类似场地工程应用提供了参考。     

The inclination and shape factors for the bearing capacity of footings

In 1920, Prandtl published an analytical solution for the bearing capacity of a maximum strip load on a weightless infinite half-space. Prandtl subdivided the sliding soil component into three zones: two triangular zones on the edges and a wedge-shaped zone in between the triangular zones that has a logarithmic spiral form. The solution was extended by Reissner (1924) with a surrounding surcharge. Nowadays, a more extended version of Prandtl׳s formula exists for the bearing capacity. This extended formulation has an additional bearing capacity coefficient for the soil weight and additional correction factors for inclined loads and non-infinite strip loads. This extended version is known in some countries as “The equation of Meyerhof”, and in other countries as “The equation of Brinch Hansen”, because both men have separately published solutions for these additional correction factors. In this paper, we numerically solve the stresses in the wedge zone and derive the corresponding bearing capacity coefficients and inclination and shape factors. The inclination factors are also analytically solved.     

Effective installation of micropiles to enhance bearing capacity of micropiled raft

While micropiles are used in many geotechnical projects, as ground reinforcement rather than as structural elements, field engineers have reported that the bearing capacity of micropiled rafts greatly exceeds the range of common ground reinforcement. This is known to be due to the confining effects of micropiles from the interaction between the ground and the micropiles, which extends the failure area of the ground significantly. Utilizing micropiles as ground reinforcement can excessively underestimate the structural contribution of the footing in a micropiled-raft system to the bearing capacity. This study investigates the support characteristics of a micropiled raft through model tests and a numerical analysis. The support behavior of the micropiled raft is evaluated for various conditions, such as soil type, pile length, and installation angle. It is found that the micropiles modify the failure behavior of the ground considerably, and that the bearing resistance can be enhanced by considering the appropriate failure mode, installation angle, and pile length.     

运用通行能力理论计算公路的发展

为建立一套科学的公路评价指标及计算方法 ,准确计算和分析现有公路的发展水平及发展速度 ,阐述了应用通行能力综合反映公路规模和效能的方法 ,在实际应用中证实了该方法的实用性和在公路管理中的重要性。     

内填砌体的密肋复合墙体极限承载力计算

结合课题组前期的研究成果,就一种新型结构的主要受力构件——密肋复合墙体的极限承载力进行研究。建立了偏心受压和偏心受拉复合墙体斜截面受剪承载力计算公式,并就影响墙体斜截面受剪承载力的因素进行了讨论;建立了墙体正截面压弯、拉弯承载力实用计算公式,并给出了墙体最终发生弯、剪破坏模式的判定。理论研究与试验分析表明:依据极限平衡理论,采用理论与经验相结合建立起来的复合墙体斜截面受剪承载力计算公式和以应变平截面假定为基础,理论推导所得的复合墙体正截面承载力计算公式,具有一定的理论依据和实用价值,满足实际工程计算需要。     

袖阀管双液灌浆提高桩承载力的设计与施工

结合工程概况,介绍了桩端注浆提高单桩承载力的机理,对灌浆加固设计技术要点进行了阐述,并论述了袖阀管灌浆法的施工工艺及其加固施工技术要点,实践证明,该法在桩基加固处理、提高桩基综合承载力和减少沉降量方面有着广泛的应用前景。     

神经网络纤维布加固钢筋混凝土梁承载力预测

建立了纤维布加固钢筋混凝土梁承载力BP神经网络模型,并用BP神经网络模型对纤维布加固钢筋混凝土的试验梁的承载力进行了预测,指出预测结果与试验结果比较接近,从而满足工程应用的要求。     

后张拉整体成形穹顶的极限承载力试验研究

本文研究的是一种新型张拉穹顶结构的承载力性能．通过后张拉闭合单弦杆平板网架中的预留缝隙,单弦杆平板网架可以张拉变形为具有很好外观形式的空间穹顶结构．成形后的单弦杆穹顶具有很好的整体刚度和承载力,可以充分发挥拱壳作用,平面外腹杆的使用延缓了穹顶整体失稳的发生,使其受力性能介于普通单层、双层穹顶网壳结构之间．     

改变结构体系后地基基础可靠性分析

本文针对改变结构体系后地基基础可靠性分析,明确了新旧地基基础在地基承载力和地基变形中的差别,重点分析了旧基础在原较大荷载作用下产生的附加应力对地基现阶段变形的影响。     

Two dimensional experimental study for the behaviour of surface footings on unreinforced and reinforced sand beds overlying soft pockets

This paper presents results of a comprehensive investigation undertaken to quantify the efficiency of using reinforcement layers in order to enhance the bearing capacity of soils that are characterised by the existence of localised soft pockets. Small-scale model experiments using two dimensional tank were conducted with beds created from well graded sand with mean particle size of 300 μm but prepared with different dry densities. A relatively softer material was embedded at predetermined locations within the sand beds so as to represent localised soft pockets. Various arrangements of soil reinforcement were tested and compared against comparable tests but without reinforcement. In total 42 tests were carried out in order to study the effect of the width and depth of the soft pocket, the depth of one reinforcing layer and the length and number of reinforcing layers on the soil bearing capacity. The results show clearly that the ultimate bearing capacity reduces by up to 70% due to the presence of a soft pocket. It was also noted that the proximity of the soft pocket also influenced the bearing capacity. Reinforcing the soil with a single layer or increasing the length of reinforcement is not as effective as was anticipated based on previous studies. However, bearing capacity increased significantly (up to 4 times) to that of unreinforced sand when four layers of reinforcement were embedded. The results suggest that rupture of the bottom reinforcement layer is imminent in heavily reinforced sand beds overlying soft pockets and therefore its tensile strength is critical for successful reinforcement.     

Radial consolidation of PVD-Installed normally consolidated soil with discharge capacity reduction using large-strain theory

The radial consolidation rate of prefabricated vertical drain (PVD)-installed soft deposits is known to be closely related to the PVD discharge capacity, which usually decreases during consolidation. Conventional solutions for radial consolidation of PVD-installed deposits have been developed to consider discharge capacity reduction using small-strain theory, in which the volume compressibility coefficient and soil permeability were assumed to be constant. This paper formulates a general expression for discharge capacity reduction with time in numerical analysis based on large-strain theory. Soil disturbance effects caused by PVD installation, such as a nonlinear distribution for radial hydraulic conductivity, are captured in the proposed solution. The proposed solution was applied to field data from a test embankment at Saga Airport. The proposed solution provides a good result which is close to the measured data.     

轻砌块承重开洞墙体承受竖向荷载的性能研究

应用有限元分析方法对开有门洞口和窗洞口的轻砌块承重墙体在竖向荷载作用下的破坏特征及变形形态进行了分析,研究其在竖向荷载作用下受力性能,并得出墙体在竖向荷载作用下的应力分布规律。     

黄土地区墓坑处理及复合地基变形分析

通过西安地区黄土地基某工程实例，介绍了墓坑地基的处理，对处理过的墓坑应注意验收；整片钻孔夯扩碎石桩二次加固地基后，通过在墓坑和天然土上做单桩复合地基静载试验，并在沉降曲线和复合地基变形模量两个方面进行对比分析，指出了它们的承载变形性关差异，地未处理墓坑位置第三次加固并验收；最后以本场地墓坑处理的效果提出了其存在的问题及建议。     

黄土地基中静压桩单桩竖向承载力的试验分析

通过某工程采用静力压桩施工工艺完成的钢筋混凝土预制桩及单桩竖向承载力的试验,对单桩竖向极限承载力的性状及影响单桩竖向极限承载力的因素进行了分析,建议单桩竖向极限承载力的估算方法作为参考。     

粉煤灰（HAB）砌块组合墙承载能力试验研究

1　前言为保护生态环境 ,保护我们赖以生存的土地 ,以传统粘土砖作为砌筑墙体的主要材料的时代即将结束。随着国家墙体改革的不断深入 ,替代粘土砖的新型墙体材料不断出现 ,其中各种孔型的小型混凝土空心砌块等已应用到承重墙体中。辽宁建科粉煤灰技术研究所研制的粉煤灰(ＨＡＢ)混凝土小型空心砌块 [以下简称粉煤灰(ＨＡＢ)砌块 ],是粉煤灰应用技术研究成功的结果。其特点是 :①粉煤灰掺量大 ;②生产工艺简单 ,免蒸免烧 ,节省能源 ;③产品质量好 ,强度高 ,符合ＧＢ/Ｔ15 2 2 9《轻集料混凝土小型空心砌块》国家标准 ;④产品成本低 ,具广泛…     

复合地基承载力检测技术探讨

以某学校综合楼地基处理工程为例,对复合地基承载力检测技术进行了介绍,分别阐述了承压板尺寸的选择,最大加载压力的确定等检测要点及相关技术要求,为检测人员提供了借鉴和参考。     

Estimation of bearing capacity of basalts at the Atasu dam site,Turkey

This paper describes the results of the engineering geological investigations and bearing capacity studies carried out at the proposed site of the rock fill Atasu Dam, to be constructed on basalts and pyroclastics. Rock mass strength and modulus of elasticity of the rock mass were determined using the Hoek–Brown empirical strength criterion. Rock mass classifications for the dam rock foundation were undertaken following the RMR, Q and GSI systems and the stress distributions using the finite element technique. To estimate the bearing capacity of the basalts, different empirical equations were used and compared.      

钢结构应力腐蚀对承载力的影响分析

在介绍应力腐蚀相关概念的基础上,重点论述了钢结构应力腐蚀对承载力的影响,并给出了应力腐蚀断裂的可能性判断依据,以促进钢结构应力腐蚀的研究发展,防止钢结构应力腐蚀的发生。     

外包钢-混凝土组合梁节点抗剪承载力研究

分析了U形外包钢-混凝土组合梁与钢管混凝土柱节点中钢管与混凝土在轴力、弯矩和剪力作用下的应力,提出新型外包钢-混凝土组合梁与钢管混凝土柱连接下节点的抗剪承载力计算公式,为这种新型结构形式的推广应用奠定了基础。