Installation Technology of Super High-rise Steel Structure of Dalian World Trade Building
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**Installation Technology of Super High-Rise Steel Structure in the Dalian World Trade Building: A Case Study**
Yan Xinglong, Gaoping
1. The First Division of China Construction Engineering Bureau, Beijing 100077;
2. Department of Investment and Engineering Management, Northeast University of Finance and Economics, Dalian 6023
This article discusses the installation techniques for the super high-rise steel structure of the Dalian World Trade Building. It covers key aspects such as beam and column selection, lifting methods, measurement correction, high-strength bolt installation, and welding of profiled steel plates.
The connection between prismatic column webs is achieved through high-strength bolts, while the pallet connections use full penetration welding. Box-shaped columns are connected via penetration welding. Beam-to-column and beam-to-beam connections typically use high-strength bolts on the web, while partial flange connections are done with full welding. Connections between beams and core tubes involve high-strength bolts on the web and vertical welds between the connection plate and embedded plates. Hinged nodes are formed by not connecting the top and bottom edge plates to the embedded parts. A total of 193 large hexagon head high-strength bolts are used for temporary connections, while the rest employ torsion-shear type bolts.
For the steel structure installation, the main building's side columns have a center distance of 38.3 meters east-west and 37.4 meters north-south. The tallest component reaches 12.51 meters, and the core tube is arranged according to the project’s specific needs. A tower crane is selected for the kitchen area on the south side of the 15th floor. Two cranes are used for finishing the structure and southern components of the podium.
Before installation, water running is conducted around the main building, with each standard floor divided into sections. Each column is split into 17 segments from ground level. The installation sequence is planned in advance, with each component assigned a unique number and position. This sequence includes details like component name, drawing number, bolt count, weight, and description.
Components are delivered in the reverse order of installation to prevent confusion. All materials must be accompanied by quality certificates and retest reports. Pre-inspection data, including weld appearance, ultrasonic testing, and dimensional deviation, are recorded before installation.
Before hoisting, all components are inspected for dimensions, bolt hole positions, and welding grooves. Column positioning axes are marked on-site, and elevation lines are projected to the next column. Elevation control lines are set for every two installed columns to ensure alignment.
During column installation, lifting points are placed at the bolt hole positions of the column ear plates. A special spreader is used with a tower crane. Shims and wedges are prepared for calibration. Temporary connection plates are fixed with high-strength bolts, and adjustments are made to correct twist.
Before hoisting beams, the outer frame around the core tube is lifted first, ensuring no interference with laminated steel plate installation. Temporary support points are set using angle steel. The sling angle must be at least 45 degrees, and binding must be secure. Connection plates and high-strength bolts are hung on both ends of the beam.
Beams are lifted in the order of main, secondary, and small beams. The middle beam is installed after the lower one. Each beam’s sling is placed in the hook, and wire ropes are used to press down the upper beams.
After placement, components are aligned, and high-strength bolts are inserted and temporarily fixed. Tightening starts from the center and moves outward. After all main beams are hoisted, initial and final tightening of high-strength bolts is performed. Weld shrinkage is reserved based on test results.
Columns connected to beams must be checked using two theodolites from different directions. Ground elevation lines and column center lines are verified. Verticality is monitored within the core tube. If deviation occurs during beam installation, the column must be corrected.
High-strength bolts used in this project are torsion-shear type, with specifications of M16, M20, and M22. Before installation, they are tested for anti-slip coefficients and surface cleanliness. Only qualified personnel can install them.
After hoisting, each node is aligned with over-boring punches to ensure free bolt penetration. Bolts are installed in remaining holes, and punches are removed after tightening. Final tightening follows an order from upper to lower and center to circumference.
On-site welding uses manual arc welding for column-to-column and beam-to-beam connections. DC welding machines (model 1400) and low-hydrogen electrodes (E4315) are used. Electrodes are baked at 300–350°C and stored at 100°C. They are kept in heat preservation tubes and re-baked if unused for more than 1 hour.
Welders must be certified. Pre-welding tests are conducted to determine welding parameters. Before welding, bevels and starting plates are checked. Ambient temperature must not fall below 0°C, with preheating and post-heating required if necessary. Wind speeds above 5 m/s require wind shields.
Welding sequences follow symmetry and node-based approaches. Beams are welded first, then columns. Top beams are welded before lower ones, and middle beams last. Symmetrical welding is performed on both sides of columns to avoid uneven heating and distortion.
Anti-deformation measures include starting welding from the center of the structure and working outward. Columns are welded symmetrically, and welders monitor column and beam measurements throughout. Any abnormalities are addressed immediately, and detailed records are kept.
Post-weld inspection includes visual and ultrasonic testing. Most welds are grade 1, except for fillet welds to embedded parts. Defects are repaired using the same process and standards.
For the profiled steel plate construction, cold-rolled steel plates are used for the Beijing Botanical Garden Exhibition Greenhouse. These plates are installed synchronously with the steel structure, with shear connectors (studs) welded to the beams. Studs are inspected for defects and tested for strength.
This project represents a complex and innovative steel structure, featuring curved pipe trusses and point-connected glass curtain walls. The design requires precise installation and high-quality welding, making it a significant case study in modern steel construction.