Study on the Fire Behavior of Sandwich Wall Panels with GFRP Skins and a Wood-Web Core

To investigate the temperature field and residual bearing capacity of the sandwich wall panels with GFRP skins and a wood-web core under a fire,three sandwich walls were tested.One of them was used for static load test and the other two for the one-side fire tests.Besides,temperature probe points were set on the sandwich walls to obtain the temperature distribution.Meanwhile,the model of the sandwich wall was established in the finite element software by the method of core material stiffness equivalent.The temperature distribution and performance reduction of materials were also considered.The residual bearing capacity of specimens after fire exposure were simulated considering the effects of web spacing,wall panel thickness and fire exposure time.Because the sandwich wall panels were stressed by eccentric compression after a fire,the residual compressive strength of the wall panel after the fire can be calculated through the eccentric loading analysis.Compared with the numerical results,it can be concluded that the effectiveness of calculation method of residual bearing capacity after fire exposure was proved.

A Theoretical Study the Effect of Openings in Infill Wall Panels on the Behavior of Structures

Two dimensional,reinforced concrete building frames built on raft foundation and having infill wall panels with openings in them are analysed using the direct stiffness method.Beams and columns are modelled by beam column elements.Wall panels are modelled by plane stress finite elements.The raft foundation is modelled by uniaxial finite elements.The soil is modelled as half space model.Openings in wall panels are introduced by using fictitious beams between real floor beams. A computer program is written to carry out the static analysis and do the necessary comparison to show the effect of openings on the structural behavior.

强震区隧道洞口段新型墙-板抗减震措施的效果分析

为了进一步提高强震区铁路隧道的安全以及抗震性能,依托包银铁路甘德尔山隧道,运用数值模拟软件FLAC 3D,针对强震区隧道洞口段墙-板和墙-板-减震层的抗减震作用效果进行研究。研究结果表明,与不采用抗减震措施相比较,采取墙-板抗震措施后,横向位移减小了5.95%,竖向位移减小了45.87%,最小安全系数增大了40.91%~49.25%,最大主应力的抗震作用效果达到了63.56%,最小主应力的抗震作用效果为4.04%,最大剪应力抗震作用效果为8.35%;采取墙-板-减震层减震措施后,横向位移减小了13.11%,竖向位移减小了43.88%,最小安全系数增大了65.82%~74.50%,最大主应力的减震作用效果达到了75.11%,最小主应力的减震作用效果为10.21%,最大剪应力减震作用效果为12.80%。采用墙-板-减震层的抗减震措施优于墙-板结构。推荐采用墙-板-减震层措施对甘德尔山隧道进行抗减震加固设计。

Seismic earth pressures on flexible cantilever retaining walls with deformable inclusions

In this study, the results of 1-g shaking table tests performed on small-scale flexible cantilever wallmodels retaining composite backfill made of a deformable geofoam inclusion and granular cohesionlessmaterial were presented. Two different polystyrene materials were utilized as deformable inclusions.Lateral dynamic earth pressures and wall displacements at different elevations of the retaining wallmodel were monitored during the tests. The earth pressures and displacements of the retaining wallswith deformable inclusions were compared with those of the models without geofoam inclusions.Comparisons indicated that geofoam panels of low stiffness installed against the retaining wall modelaffect displacement and dynamic lateral pressure profile along the wall height. Depending on the inclusioncharacteristics and the wall flexibility, up to 50% reduction in dynamic earth pressures wasobserved. The efficiency of load and displacement reduction decreased as the flexibility ratio of the wallmodel increased. On the other hand, dynamic load reduction efficiency of the deformable inclusionincreased as the amplitude and frequency ratio of the seismic excitation increased. Relative flexibility ofthe deformable layer （the thickness and the elastic stiffness of the polystyrene material） played animportant role in the amount of load reduction. Dynamic earth pressure coefficients were compared withthose calculated with an analytical approach. Pressure coefficients calculated with this method werefound to be in good agreement with the results of the tests performed on the wall model having lowflexibility ratio. It was observed that deformable inclusions reduce residual wall stresses observed at theend of seismic excitation thus contributing to the post-earthquake stability of the retaining wall. Thegraphs presented within this paper regarding the dynamic earth pressure coefficients versus the wallflexibility and inclusion characteristics may serve for the seismic design of full-scale retaining walls withdeformable polystyrene inclusions. 2014 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Production and hosting byElsevier B.V. All rights reserved.

Effect of Wall Charge on Striation in Plasma Display Cells

Different configurations and driving voltages have been employed to investigate the effect of the wall charge on the striations in macroscopic plasma display panel （PDP） cells. The experimental results show that a discharge channel near the dielectric layer is indispensable to striation occurring in the anode area during a discharge, while the pre-accumulated charge on the dielectric layer and the surface state are not important. The origin of the striation is related only to the physical process in the cell. The dielectric layer acts as a charge collector during a PDP discharge.

A New Method for Measuring the Wall Charge Waveforms of AC PDP

A new method is developed to measure the wall charge waveforms in coplanar alternating current plasma display panel (AC PDP). In the method, two groups of display electrodes are selected from a coplanar AC PDP and two capacitors are respectively connected with these two groups of display electrodes in series, and a measuring circuit and a reference circuit are thus constructed. With the help of special processing, discharge takes place in the cells included in the measuring circuit under a normal drive voltage but no discharge takes place in the cells included in the reference circuit under a normal drive voltage. The wall charge waveforms are obtained from the voltage difference between the two capacitors. Using the method, the wall charge waveforms are measured during resetting period, addressing period and sustaining period for the 304.8mm (12-inch) test PDP panel. The result shows that the wall voltage is about 96V during the sustaining period.

Design and Fabrication of Aluminum Cladding and Curtain Wall of a Sports Club

The paper discusses the design, fabrication and the execution of the cladding supported by steel trusses and curtain wall of a sports club. The cladding and the curtain walls were subjected to a wind load of 1.2 Kpa considering basic wind speed of 25 m/s as per the project specifications. The first part of the paper deals with the cladding work of the canopy that consist of a 4 mm thick aluminium composite panels supported by steel trusses extended from the main structure. Two types of steel trusses were provided, the main truss connected to the space truss, whereas the intermediate truss connected to channels. Both trusses were spaced at 2.5 m centre to centre. These trusses were fabricated at factory and transported to the site for installation. The second part of the paper is related to the curtain wall design having Maximum Mullion spacing of 2 m, considered as worst scenario for the design calculations. The maximum Mullion height was 5.55 m, adopted in the calculations with bottom and top pinned connection. The Technal system was adopted for the design of mullions and transoms. Design was carried out using numerical modeling with CSI SAP2000 for cladding and its supporting structures. The bracket was realized and checked for the corresponding induced forces. All the structural systems were found safe according to different acceptance criterion.

Shear reinforcement effect of reinforced concrete tie-columns on the lateral resistance of confined masonry walls

Tie-columns improve significantly the lateral resistance of masonry bearing walls against persistent, transient and accidental loads. The research work described herein has been carried out to assess the lateral resistance of confined masonry walls, where contribution of the masonry panel is evaluated according to material mechanics and tie-columns effect is estimated by a proposed analytical formulation based on a model reported on previously. This approach takes into account the effect of dowel support on the reaction of its adjacent shear reinforcement： the conditions for the various contributions of transverse reinforcements are better defined following a clear evaluation of the participation ratio of these reinforcements. Lateral resistances of confined masonry walls measured in full-scale tests and gleaned from the literature are compared and checked with resistances calculated using the present approach.

轻钢龙骨混凝土复合外挂墙板力学性能试验研究

复合墙板性能关系着结构的安全,在新设计建造的轻钢龙骨复合墙板投入使用前应进行力学性能试验,以评估其安全性能。为研究墙板的受力变形过程及破坏形态,对两片不同的轻钢龙骨混凝土复合外挂墙板分别进行四点弯曲试验和低周反复荷载试验。弯曲试验结果表明,弯曲过程中墙板出现裂缝时的计算等效均布荷载大于建筑风荷载标准值,抗弯性能满足受力要求。墙板经历了弹性阶段、弹塑性变形阶段和屈服破坏阶段,主要通过钢材屈服后的弹塑性变形和材料的破坏来实现耗能,屈服前耗能占总耗能的6.19%,屈服后累计耗能呈现二次抛物线增长,这一结果体现了墙板良好的抗震能力。研究结果可为实际应用提供依据。

外挂墙板施工阶段碳排放的智能监测与优化

建筑行业的温室气体过量排放逐渐引起了人们的关注,且其施工阶段往往面临成本超标、工期延长和碳排放失控等问题,因此,建筑施工阶段碳排放的监测与多目标优化问题成为目前研究重点。为了有效解决上述问题,从物理层、计算层和交互层三部分提出了监测优化系统的框架;以Revit为二次开发平台、利用MySQL建立数据库,搭建了碳排放智能监测与优化平台;以外挂墙板构件施工过程为例,运用融入柔性理念的遗传算法寻找出使得“成本工期碳排放”综合目标最适合项目特征的工序执行模式组合及最优解。研究为装配式建筑施工阶段的碳排放监测与优化提供了一套科学、高效的集成化管理技术。

外附轻质墙板的弱轴全螺栓装配式钢框架试验研究

为实现钢框架H型钢柱的弱轴连接,设计了一种悬臂段H型钢梁柱的弱轴顶底L型件连接钢框架,并将保温装饰轻质墙板作为围护结构外挂于钢框架。对1榀单层单跨1∶2缩尺试件进行抗震试验研究,分析结构体系的整体破坏模式、承载力、刚度以及耗能能力的变化,评价外挂轻质墙板体系的整体性能。结果表明:外挂轻质墙板全螺栓装配式弱轴连接钢框架的破坏模式合理,墙板体系稳定,L型件连接节点实现了梁端塑性铰外移。结构滞回曲线饱满,骨架曲线呈S型,正向屈服位移与极限承载力分别为27.08 mm与351.99 kN,负向为19.78 mm和377.43 kN,满足结构延性与承载力需求;试件塑性刚度退化缓慢,最大阻尼比达0.35,整体耗能性能较好。外挂墙板的干挂形式与钢框架的全螺栓连接方法共同提高了建筑装配化效率。

结构-功能一体化异种复合材料壁板优化与验证

基于航空壁板结构承载-电气功能的一体化需求,对适用于智能蒙皮的异种复合材料壁板开展了优化设计与试验验证。通过在高模量碳纤维蒙皮的外侧增加玻璃纤维层,进行了以碳纤维-玻璃纤维-金属结构单元阵列-玻璃纤维复合顺序的壁板承载-电气功能一体化设计。针对异种复合材料结构的铺层优化需要考虑共胶接的分区域及铺层连续性的工艺要求,发展了基于丢层序列的优化方法,并对于加筋壁板的几何外形、筋条数量、筋条几何参数以及筋条与蒙皮的铺层角度进行了优化设计。通过压缩稳定性试验验证了该结构在承载能力和稳定性方面的收益,明晰了其压缩载荷下的屈曲模态及后屈曲失效机理。

冷弯薄壁型钢-结构防火一体板自攻螺钉连接性能试验研究

开展冷弯薄壁型钢-结构防火一体板自攻螺钉连接抗剪性能试验研究,完成35个典型试件单调拉伸及低周往复加载试验,分析结构防火一体板厚度、螺钉直径、螺钉端距及加载角度等因素对其抗剪性能的影响。结果表明:不同加载角度及螺钉端距的试件呈现不同的破坏模式,主要包括板材端部撕裂破坏、板材孔壁承压破坏、板材被拉断破坏等,且破坏时试件的自攻螺钉存在不同程度的倾斜。对于试验端分别采用直径为4.8、5.5 mm螺钉的试件,试件的峰值荷载及延性系数与螺钉直径无明显相关性,弹性刚度随着螺钉直径增大而显著提升;随着螺钉端距由15 mm增大至25 mm,试件的弹性刚度无明显变化,而峰值荷载和延性系数提高了约35%;随着板厚由12 mm增大到20 mm,试件的峰值荷载提高了约40%,弹性刚度提高了约90%,延性系数降低了约30%;与加载角度为0°的试件的特征参数相比,加载角度为45°时,试件弹性刚度提高了约100%,峰值荷载及延性系数无明显差别;加载角度为90°时,试件弹性刚度及峰值荷载无明显差别,延性系数降低了约40%。

一种新型结构与保温一体化复合墙板节点试验

为解决复合墙板节点常见的保温板易燃、易脱落等棘手问题,并使其抗震性能良好。给出了一种新型的结构与保温一体化陶粒混凝土T型复合墙板节点。该复合墙板节点具有夹芯独特构造优势,主要表现在绿色节能,轻质高强,力学性能好,保温系统连接可靠,还能杜绝火灾的发生。通过对T型复合墙板节点进行抗震试验,分别研究了其滞回性能、破坏机理、承载及变形能力、延性、耗能、损伤等。结果表明:一体化复合墙板节点的破坏顺序为腹板-翼缘-节点核心区;薄弱位置主要发生在腹板脚部,混凝土被拉裂或压碎,钢筋被拉长或压弯等;节点核心区受力相对良好,安全储备充足;符合“强节点,弱构件”设计要求和墙板革新发展政策。延性系数大于3,墙板节点安全性能良好。通过损伤指标评估分析,了解了试件各阶段工作状态。

预制混凝土复合外挂墙板的研究现状

装配式建筑结构具有抗震性能良好、低碳环保、施工便利等优点,是适应绿色建筑发展、响应节能减排战略的新型建筑结构体系。预制混凝土复合外挂墙板作为装配式建筑工程的子项目,性能优异,发展潜力巨大。综述了预制混凝土复合外挂墙板的研究现状,从热工性能、力学性能、抗震性能等多方面展开研究,既对墙板的设计和运用具有重要意义,又能为节能减排战略和绿色建筑发展做出贡献。

加气混凝土复合保温外墙板连接节点试验研究

通过对钢管锚节点、套筒节点和新型F型节点进行的6组加气混凝土板四分点加载节点极限承载力试验,分析不同板厚下3种节点的节点强度、节点刚度等性能指标。研究表明:新型F型节点力学性能良好,连接可靠,节点极限承载力随板厚增加而增大。新型F型节点可较好地适用在加气混凝土复合保温外墙板体系中。

轻钢龙骨复合保温外墙板抗弯性能研究

为了研究轻钢龙骨复合保温外墙板的抗弯性能,采用有限元分析软件ABAQUS对墙板进行了模拟分析,并与已有研究进行对比。研究了轻钢龙骨和覆面板等参数对墙板抗弯性能的影响,并对比了风荷载下墙板的正常使用情况。基于装配式钢结构建筑对外墙板的性能要求,提出了一种由轻钢龙骨、覆面板、保温层和防护层组成的轻钢龙骨复合保温外墙板。研究表明:该墙板的整体受力性能较好,其中增加轻钢龙骨腹板高度对墙板影响最显著,与龙骨腹板高度为100 mm时相比,高度为120、150、180 mm时墙板屈服荷载提高了39.31%、71.92%和101.3%,极限荷载提高了42.48%、72.9%、104.53%,有无龙骨加强肋几乎不影响墙板的抗弯性能。

新型轻质装饰结构一体化墙体单元拼接部位热工性能研究

对于装配式建筑来说,其墙板拼接部位通常存在热桥缺陷,是影响其系统整体热工性能的重要因素,进而造成墙体传热量计算出现偏差。本文针对一种新型的轻质装饰结构一体化墙体单元拼接部位的热工性能进行了系统研究,通过截取有效计算单元,以有拼接缝有无隔热填充、不同勾条材质等为基本参数,利用有限元软件Therm进行了二维稳态热工仿真分析,得到了在不同参数条件下的热工性能变化规律,并提出了后续优化设计建议。

南昌东站插接离缝式双曲铝板幕墙施工技术

南昌东站高架层候车厅外侧28个幕墙铝板开花柱造型,是南昌东站标志性建筑造型结构,全部由双曲异型铝板拼接组合而成,加工及施工难度高。针对该结构造型的龙骨、饰面及细部做法进行详细拆解剖析,通过全流程要点控制,最终实现高品质的外观效果。该工程在既有BIM技术支持下,充分挖掘提升联合下单潜力,有效指导双曲铝板加工、安装,以实现设计效果。同时,通过预焊接、装配式等措施方法,显著提升标准化模块复制施工效率,并保障施工效果整齐划一。预组装龙骨、插接离缝式铝板插接工艺、全异型石材柱脚等工艺做法均可为类似工程提供参考。

BF型钢EPS泡沫混凝土外挂墙板有限元分析

为研究玄武岩纤维对型钢EPS泡沫混凝土预制外挂墙板的作用影响,本文通过棱柱体试验以及相关文献获得不同掺量玄武岩纤维的EPS泡沫混凝土的本构曲线,利用有限元软件ABAQUS对预制墙板进行有限元分析,探究其不同掺量时对EPS轻骨料混凝土力学性能的影响规律。研究结果表明:当玄武岩纤维掺量为0.2%时,对构件承载力有明显提升;而当玄武岩纤维掺量为0.6%时,对构件承载力几乎没有提升,且延性有所下降。因此,最佳掺量为2%。此外,冷弯薄壁C型钢与EPS泡沫混凝土之间具有较高黏结强度,且掺入玄武岩纤维不改变墙板的破坏模式。