Reliability-Based Design and Second-order Analysis of Temporary Structures Used in Building Construction

• Main Authors: Chung-Sheng Wang, 王鍾勝
• Other Authors: Jui-Lin Peng
• Format: Others
• Language: zh-TW
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/6c2e53

博士 === 國立雲林科技大學 === 工程科技研究所 === 106 === The importance of dismantling contemporary construction after finishing the construction often is neglected by the builder. Above all the collapse cases happened in the construction sector, the severest one is that heavy casualties caused by the collapse of the Falsework. Besides, in order to cooperate with Urban Renewal, it is common that accidents caused by exterior walls renovation project scaffolding collapse. It bring about not only the constructors casualties problems but also passengers. Now the design of contemporary construction in Taiwan, we often use ASD of Elastic Analysis in Steel structure design. This kind of method only considers the safety factors of the structure which cannot evaluate the shoring structure load capacities which is close to the reality of LRFD. This research is based on the Reliability-Based Design, building falsework on load factors and the strength reduction factor to replace the「ASD」in Safety Factor ,to provide the design of the falsework. Nowadays, the rule of the steel structure design in the developed countries, such as Europe or the U.S. A. is that they should use second-order analysis. We can directly simulate the structure after loading dynamic behaviors, which can evaluate the load capacities or failure model correctly. This study discuss about dynamic behaviors of compound falsework. We take second-order analysis and full-size compound falsework indoor and outdoor structure load test in order to prove the accuracy of the second-order analysis. Moreover, the study focus on the second-order analysis used in the outer wall fixing scaffolding, at the same time, to confirm the reasons of collapse and failure model. According to the results of the research, setting jack base under the scaffolding can rise the load-bearing capacity of the scaffolding. It won’t have much effect if setting the upper U base. The load-bearing capacity in combined scaffolds only reaches half lead-bearing capacity with the same height of only one kind scaffolding. The load-bearing capacity of the scaffolding will rise complying with the number of the scaffolding, not with the multiple of the scaffolding. According to the experiment of outdoor combined setup, it can achieve the lateral bracing reinforcement effect without supporting capacity on the top. Using the Second-order Analysis to simulate the combined setup, we can get the destroyed mode which is much more accurate and close to the reality. It can also be beneficial to rising the supporting system of the safety assessment. The foot pedal of the scaffolding of out wall can restrain the scaffolding to become deformed, and at the same time, rise the load-bearing capacity of the unilateral cross-bar. It made no difference with bilateral cross-bar. It should take notice that scaffolding built at the entrance destroy the cross-bar. When the lateral force of scaffolding of out wall renovation project is getting stronger, the structure of the scaffolding gets lower. According to this research, we can use the axial-force and bending moment relation chart as reference when designing scaffolding of the renovation project.