Experimental Study of Load Capacities and Failure Models of Façade Scaffolds Used in Building Construction

• Main Authors: Yu-Rui Xu, 許育睿
• Other Authors: How-Ji Chen
• Format: Others
• Language: zh-TW
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/pcfww3

碩士 === 國立中興大學 === 土木工程學系所 === 104 === In the process of construction engineering, it is necessary to build some temporary constructions like scaffolds to provide working platforms for workers.This temporary construction will have a variety of configurations due to different shapes and appearances of buildings or distinct terrains. Different configurations will influence the bearing capacity and destructive behaviors of scaffolds. The research is about carrying out experiments on the façade scaffolds which are commonly used in building field. The research shows that it is important to set up cross brace in both sides of scaffolds. It causes greatly decrease in the bearing capacity of scaffolds when removing inner cross brace, and therefore it is not recommended to remove it. However, if it is for the convenience of construction, inner cross brace can be replaced by qualified guard rails. No matter in individual configuration or systematic configuartion, or in the experiment of bondary condition supporting capacity of scaffolds, the test results show that the bearing capacity of guard rails is similar to nomal scaffold. In different boundary conditions, it may have different constructions reactions. If we cut out the plane of a screw jacks, the base can be seen as in the form of articulation because of the absence of plane which can resist bending moments. We can simulate it as a scaffolds which starts from the second floor, and it has the worst bearing capacity ; A scaffolds with a baseboard can be simulated as a scaffolds from the ground. Because the degree of junction of base and main steel tube is not too high, the strength is in the second place; Removing the screw jack and let the main steel tube be directly in contact with the ground gets the strongest testing strength. However, the scaffolds should be adjusted using the base in reality, so it is not recommended to apply the method. The walk board just provides the stability of the scaffold shape, and it has a little contribution to the scaffolds. In the aspect of the coupler strength, if two main tubes are parallel, the strength will be the best for a 8-clamp, and the second for a clamp. Iron wire can just provide temporary stability use, so it is not recommend to use it for coupling. In the concave-convex places like balconies of buildings, the space is less than the width of the working platform. If we just use iron wire to connect walk board to stretch to the concave-convex places, it will have huge distortion and have safety problems. Therefore, we recommend to use single-tube scaffolds to build the working platform. The destruction control of scaffolds is determined by the coupler strength of frame. Using a 8-clamp to couple will have better bearing capacity, and the second for a clamp. The strength of bracket is influeced by bolts. Using a bolt which has better endurance and strength will increase the entire strength of a bracket. The destruction place of an exit is in the locking nail failure of crossing brace in the scaffolds. It is not the whole platform destruction but partial destruction of configuration. When it is overloading, the locking nail will be destoryed immediately, and the loading strength of the working platform is about 4 tonf . As for the tube cover of the 3rd reinforced, in the condition of tube cover 1.5m as well as hinge in both sides, it can support 4.1 tonf axial pressure. Therefore, if the rod is used and the amount is sufficient, we can ignore the destruction of steel tube cover due to pressure.