Why are the main structural columns in large automated warehouses made of precast concrete columns rather than steel structures? ? ?

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In August 2023, the second vertical warehouse of ExxonMobil Huizhou Ethylene Project Phase I, constructed by Sinopec Fourth Construction Co., Ltd., was delivered on schedule as the first warehouse in this project. 　　The No. 2 vertical warehouse of this project is currently the largest intelligent polyolefin warehouse under construction in Asia. With a total construction area of over 40,000 square meters, it is more than 300 meters long, over 150 meters wide, and over 30 meters high. It has 7 fire compartments, and its main structural framework consists of more than 200 precast concrete columns. The roof is of a spherical grid structure, giving the facility an extremely large overall size. Given the tall and large structural characteristics of Warehouse No. 2, Sihua Fourth Construction Company worked in close coordination with the project team to develop a plan, and conducted thorough discussions and calculations with the design firm; ultimately, the scheme for on-site lifting of precast column caps was adopted. 　　Warehouse 2 has over 200 precast columns, each nearly 40 meters long, with a cross-sectional dimension of 1.5×1.5 meters and a weight of around 240 tons. For prefabricated components with such a high length-to-diameter ratio and large individual weight, the project team lacked relevant construction experience to rely on; through continuous innovation, bold experimentation, and scientific calculations, they ultimately succeeded in installing the prefabricated columns. At the same time, various tasks such as the lifting of grid modules, the installation of side wall panels, the installation of fireproof partitions, and the installation of roof panels were carried out efficiently and in an orderly manner, with seamless transitions between different stages of work, thus laying the foundation for the intelligent warehouse to be delivered on schedule. On June 26, 2023, with the modular lifting of the grid structure for Warehouse D in the Sinopec Tianjin Nangang ethylene project completed, it marked the first time in the industry that the entire grid structure of a vertical warehouse was assembled. This also represented a significant step forward in the construction of a world-class, green and intelligent vertical warehouse for the Tianjin Nangang ethylene project. Once completed and put into use, it will become Sinopec’s vertical warehouse with the largest storage capacity. The solid products and packaging warehouse is an important chemical product packaging warehouse for Sinopec’s Tianjin Nangang Ethylene Project. Among them, the automated warehouse is 160 meters long, 131 meters wide, and 37.8 meters high, with a construction area of 21,550 square meters. It is equipped with 38,252 storage locations and can hold approximately 57,378 tons of polyolefin products. This automated storage facility features 112 concrete columns, with no connecting beams between them; it requires high levels of verticality and precision, making design and construction quite challenging. To address the two major challenges associated with the installation of concrete columns and steel grid structures in automated storage facilities, and to optimize the construction of such facilities, Sinopec Tianjin Branch, in collaboration with Sinopec Engineering Construction Company and Sinopec Tenth Construction Company, focused on the construction environment and emphasized innovation as a driving force. They developed new construction methods, and for the first time in China’s engineering sector, adopted a new construction approach that utilizes prefabricated concrete columns, which increases work efficiency by more than 50% compared to traditional construction methods. For the first time, a new installation method of \"ground assembly with hydraulic overall lifting + aerial filling supports\" was adopted, enabling the main structure at the top of the vertical warehouse to be installed in one go. This significantly reduces the safety risks associated with work at heights, and it opens up new possibilities for the modular construction of large-span, high-altitude grid structures in the petrochemical engineering industry.