期刊文献+
共找到4篇文章
< 1 >
每页显示 20 50 100
带小直径纵筋并外包CFRP的RC圆墩抗震性能研究 被引量:4
1
作者 薛俊青 davide lavorato +3 位作者 聂尚杰 陈俊臻 BRISEGHELLA Bruno NUTI Camillo 《中国公路学报》 EI CAS CSCD 北大核心 2022年第2期124-135,共12页
桥梁震害调查显示,钢筋混凝土(RC)桥墩易受损,影响震后救援和灾后重建。采用小直径纵筋替换受损纵筋并外包碳纤维布(CFRP)的技术修复受损桥墩可缩短震后修复周期,节省重建费用。以某不规则连续梁桥的RC圆墩为工程背景,选择小直径纵筋的... 桥梁震害调查显示,钢筋混凝土(RC)桥墩易受损,影响震后救援和灾后重建。采用小直径纵筋替换受损纵筋并外包碳纤维布(CFRP)的技术修复受损桥墩可缩短震后修复周期,节省重建费用。以某不规则连续梁桥的RC圆墩为工程背景,选择小直径纵筋的长度和直径、外包CFRP层数为参数,开展7根缩尺比例为1∶6的RC圆墩试件的拟静力试验;选用OpenSees建立有限元模型,采用试验结果验证其准确性,并开展参数分析。研究结果表明:设置小直径纵筋的桥墩的塑性变形集中在小直径纵筋高度范围内,桥墩破坏被限制在塑性铰区域内;与未设置小直径纵筋的桥墩相比,小直径纵筋使桥墩承载力降低20%~27%,但桥墩位移延性提高42%~85%,曲率延性提高47%~242%,耗能性能提高32%~56%;在满足桥墩承载力设计要求的情况下,使用小直径纵筋可有效提高桥墩抗震性能;设置小直径纵筋的桥墩在小直径纵筋区域内的实测CFRP最大应变明显大于未设置的试件,说明对设置小直径纵筋的桥墩外包CFRP,可防止桥墩过早破坏,提高延性;随着小直径纵筋长度增大或直径减小,桥墩耗能性能先增大后减小;建议以钢筋疲劳寿命需求为下限,塑性铰长度为上限选择小直径纵筋长度;选择满足保证塑性铰以外的纵筋受力始终在弹性范围内的条件下的最大直径为小直径纵筋直径;增大修复区域的混凝土强度可弥补设置小直径纵筋造成的桥墩承载力降低。 展开更多
关键词 桥梁工程 抗震性能 拟静力试验 钢筋混凝土圆形桥墩 小直径纵筋 碳纤维布
原文传递
Curved footbridges supported by a shell obtained through thrust network analysis 被引量:1
2
作者 Luigi Fenu Eleonora Congiu +2 位作者 davide lavorato Bruno Briseghella Giuseppe Carlo Marano 《Journal of Traffic and Transportation Engineering(English Edition)》 CSCD 2019年第1期65-75,共11页
After Maillart's concrete curved arch bridges were built before the Second World War, in the second half of the past century and this century, many curved bridges have been built with both steel and concrete. Conv... After Maillart's concrete curved arch bridges were built before the Second World War, in the second half of the past century and this century, many curved bridges have been built with both steel and concrete. Conversely, since the construction of Musmeci's shell supported bridge in Potenza, few shell bridges have been constructed. This paper explains how to design a curved footbridge supported by an anticlastic shell by shaping the shell via a thrust network analysis(TNA). By taking advantage of the peculiar properties of anticlastic membranes, the unconventional method of shaping a shell by a TNA is illustrated. The shell top edge that supports the deck has an assigned layout, which is provided by the road curved layout. The form of the bottom edge is obtained by the form-finding procedure as a thrust line, by applying the thrust network analysis(TNA) in a non-standard manner,shaping the shell by applying the boundary conditions and allowing relaxation. The influence of the boundary conditions on the bridge shape obtained as an envelope of thrust lines is investigated. A finite element analysis was performed. The results indicate that the obtained shell form is effective in transferring deck loads to foundations via compressive stresses and taking advantage of concrete mechanical properties. 展开更多
关键词 Shell footbridges Cantilevered deck Anticlastic shell Thrust network analysis(TNA) CONCRETE
原文传递
Probabilistic seismic response and uncertainty analysis of continuous bridges under near-fault ground motions
3
作者 Hai-Bin MA Wei-Dong ZHUO +5 位作者 davide lavorato Camillo NUTI Gabriele FIORENTINO Giuseppe Carlo MARANO Rita GRECO Bruno BRISEGHELLA 《Frontiers of Structural and Civil Engineering》 SCIE EI CSCD 2019年第6期1510-1519,共10页
Performance-based seismic design can generate predictable structure damage result with given seismic hazard.However,there are multiple sources of uncertainties in the seismic design process that can affect desired per... Performance-based seismic design can generate predictable structure damage result with given seismic hazard.However,there are multiple sources of uncertainties in the seismic design process that can affect desired performance predictability.This paper mainly focuses on the effects of near-fault pulse-like ground motions and the uncertainties in bridge modeling on the seismic demands of regular continuous highway bridges.By modeling a regular continuous bridge with OpenSees software,a series of nonlinear dynamic time-history analysis of the bridge at three different site conditions under near-fault pulse-like ground motions are carried out.The relationships between different Intensity Measure(IM)parameters and the Engineering Demand Parameter(EDP)are discussed.After selecting the peak ground acceleration as the most correlated IM parameter and the drift ratio of the bridge column as the EDP parameter,a probabilistic seismic demand model is developed for near-fault earthquake ground motions for 3 different site conditions.On this basis,the uncertainty analysis is conducted with the key sources of uncertainty during the finite element modeling.All the results are quantified by the"swing"base on the specific distribution range of each uncertainty parameter both in near-fault and far-fault cases.All the ground motions are selected from PEER database,while the bridge case study is a typical regular highway bridge designed in accordance with the Chinese Guidelines for Seismic Design of Highway Bridges.The results show that PGA is a proper IM parameter for setting up a linear probabilistic seismic demand model;damping ratio,pier diameter and concrete strength are the main uncertainty parameters during bridge modeling,which should be considered both in near-fault and far-fault ground motion cases. 展开更多
关键词 continuous bridge PROBABILISTIC SEISMIC DEMAND model INTENSITY MEASURE NEAR-FAULT uncertainty
原文传递
Asynchronous earthquake strong motion and RC bridges response
4
作者 davide lavorato Gabriele Fiorentino +4 位作者 Alessandro Vittorio Bergami Bruno Briseghella Camillo Nuti Silvia Santini Ivo Vanzi 《Journal of Traffic and Transportation Engineering(English Edition)》 2018年第6期454-466,共13页
The dynamic response of long structures(e.g., bridges) is sensitive to the spatial variability of strong ground motion(asynchronous motion). Ground motion differences increase from point to point with increasing found... The dynamic response of long structures(e.g., bridges) is sensitive to the spatial variability of strong ground motion(asynchronous motion). Ground motion differences increase from point to point with increasing foundation distance. This latter is due to two physical phenomena: soil-wave interaction, that causes the loss of coherence and local amplification; wave traveling with finite velocity, that causes signals time lag. This ground motion variability produces a different structural demand compared to the synchronous one,which is the only one considered by designers in the majority of cases. A few codes consider this type of actions, therefore further research efforts are necessary. In this study,asynchronous ground motions are generated by means of a new generation procedure implemented in the software GAS 2.0 using as input the simultaneous strong motion records from the April 6 th, 2009, L’Aquila(Italy) at the seismic stations AQA and AQV, located in the Aterno River valley. These records are used to calibrate the generation model and to produce sets of asynchronous earthquake sampling. The asynchronous earthquake sets are applied on a typical highway reinforced concrete bridge to study its dynamic response considering two different configurations: non-isolated with traditional supports and isolated bridge with lead rubber bearings. The bridge is placed in two positions along the wave propagation direction: a position near one recording station and a position between the two stations to consider local soil effects. The response parameters investigated are the maximum relative displacements of soil and deck. The results show that there is animportant variation of relative displacement along the direction of wave propagation due to asynchronous motion with effects that designer should consider for the structural details design of isolated and non-isolated bridges. 展开更多
关键词 Asynchronous motion BRIDGES Seismic response Earthquake spatial variability
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部