In recent years, with the rapid development of construction steel structure technology and the increasing degree of mechanization, and because the tensile and compressive strength of steel structure is relatively high, the cross-section of the component is small, the self weight is light, the structural performance is good, the construction speed is fast, and the environmental pollution is small, so the steel structure engineering is suitable for a variety of structural forms and places. Therefore, light steel structure engineering has been widely used. How to do the safety and quality control of steel structure is an urgent task. We need to do the quality control from the source. This requires us to understand the causes of common accidents of steel structure, analyze these causes, carry out effective governance, and ensure the safety of the project. This paper summarizes the common building quality accidents of steel structure and analyzes the causes.
1、 Common quality accidents in grid structure engineering
(1) The member is bent, deformed or partially broken.
(2) The connection of sealing plate or cone head weld is damaged.
(3) Node deformation or fracture.
(4) The weld is not full or there are bubbles, slag inclusions and micro cracks exceeding the specified standard.
2、 Common quality accidents in portal frame engineering
(1) The main components are deformed and twisted.
(2) The embedded parts do not meet the requirements of drawings and specifications, the height difference exceeds the standard, and the spacing exceeds the standard.
(3) The overall perpendicularity of the steel frame is out of tolerance with the overall plane bending, and the hole position of the end plate of the beam and column is not corresponding, and the size is misaligned.
(4) The welds of main stressed joints are not full or have bubbles, slag inclusions and micro cracks exceeding the specified standards.
1、 Design reasons
(1) The selection of structural form is unreasonable, the cross-section matching of members is unreasonable, the influence of initial bending, initial eccentricity and secondary stress of members is ignored, and the low load calculation and missing calculation or load combination are improper in design.
(2) Material selection is unreasonable.
(3) The selection of calculation method, assumption condition and computer program are not found.
(4) Wrong or incomplete drawings. If the dimensions are disordered, the design description is unclear, and there are omissions in materials, process requirements, construction procedures and special requirements.
2、 Processing reason
(1) Disordered management, mixed use of different specifications, steel grades and materials.
(2) The blanking size of the component is wrong, and the slenderness ratio of the component does not meet the design requirements.
(3) When the grid members are not cut or butt welded, the liner is not added or the welding is not in accordance with the design requirements.
(4) The connecting high-strength bolt is unqualified.
3、 Installation reason of grid structure
(1) During the ground assembly, the supporting points are uneven, the forces are unreasonable, the errors accumulate during the assembly, and the errors of individual members lead to the changes of the forces, resulting in the deformation of the grid structure or individual members.
(2) The welding process and welding sequence are wrong, resulting in welding stress and deformation.
(3) During the overall hoisting, the selection of hoisting points is unreasonable, and there is no counter force checking calculation, over stress checking calculation of members, deflection checking calculation and necessary reinforcement measures for over stress parts.
(4) During integral hoisting, the hoisting speed of each hoisting point is different, and the displacement and height difference exceed the allowable range, resulting in deformation and damage.
4、 Installation reason of portal frame
(1) During the transportation and stacking of long components, the cushion is not flat and placed for a long time, resulting in deformation and distortion.
(2) The position of embedded bolts is not correct, and there is no retest and correction during installation, which results in deformation and distortion of columns and beams, and the overall perpendicularity and plane bending of the steel frame are out of tolerance.
(3) The hole position of beam column end plate is not corresponding and misplaced. The end plate is not aligned during installation, and the bolts are not tightened in sequence.
(4) The site welding did not follow the welding procedures or the welder's technical problems, resulting in the weld not full or bubble, slag inclusion, micro cracks.
The above mentioned are common quality accidents and causes in light steel structure engineering. The construction of light steel structure engineering requires professional steel structure company. Dalian Fuxin Guangsheng Trade Co., Ltd. has independent import and export rights. The business scope of the company: import and export of goods and technology. We support the processing and production of welding structural parts, prefabricated buildings, engineering equipment, machining parts, molds and other products, with safe and reliable product quality. Since its establishment, the company has continued to carry out the export business of steel structure products in Singapore, Japan and Germany. Complete the foreign exchange settlement business of SGD, JPY and USD. And has the construction steel structure engineering contracting qualification, customized light steel structure building for you, over the years has always been adhering to the "quality satisfaction, customer first, realistic and pragmatic, strive to forge ahead" purpose. And professional construction team, advanced management mode, sincere team spirit and perfect after-sales service are the fundamental guarantee for our company to win the trust of customers. The company strictly checks the product quality and the technical personnel are responsible for it. Choosing Fuxin Guangsheng is to choose the best structural steel products!