For Phase II (Buildings B4 and B5), the client explicitly sought to overcome traditional column grid limitations and improve storage utilization. After scheme evaluation, BICP proposed a 12 m × 10 m large-span post-tensioned flat slab solution. Using a 3D finite element analysis program imported from the U.S. combined with proprietary post-tensioning optimization algorithms, the design achieved refined analysis of large-span floor loading, confirming feasibility and proceeding to construction.

Conventional cold storage facilities typically use 7–9 m column grids due to the mechanical limitations of reinforced concrete slabs: increasing span significantly raises bending moments, and without active compensation, slab thickness and reinforcement ratios escalate rapidly, affecting cost and constructability. For cold chain logistics operators, this results in: columns occupying usable floor area, restricted rack arrangement options, reduced forklift aisle efficiency, and lower usable storage volume relative to gross area. BICP adopted the Taiku large-span post-tensioned flat slab system: post-tensioning tendons are placed within the slab concrete and tensioned to introduce active compressive stress, counteracting bending moments from large spans and enabling 12 m × 10 m column spacing without substantially increasing slab thickness. Structural analysis utilized a 3D finite element program from the U.S. combined with proprietary optimization algorithms to systematically optimize tendon layout, jacking forces, and anchorage details, controlling material usage while meeting strength and crack control requirements. The design also accounted for low-temperature effects on concrete shrinkage and long-term prestress losses, incorporating temperature correction factors to ensure stable structural performance over the service life. Post-tensioning construction proceeded in stages, closely coordinated with civil works. BICP's technical team provided on-site supervision, recording threading, tensioning, and locking procedures for each tendon to ensure consistency with design values. Buildings B4 and B5 were constructed using a流水作业 (flow-line) method, with the post-tensioning team working in zones to compress the schedule while maintaining quality.

Chengdu Yinli Phase II Cold Storage Project: Taiku Large-Span Post-Tensioned Flat Slab Engineering Practice

Project Background

Chengdu Yinli Cold Chain Logistics Co., Ltd. is a major professional cold chain logistics enterprise in Southwest China. During the long-term operation of Phase I cold storage, the company identified constraints of the conventional 7–9 m column grid on storage efficiency: numerous internal columns limited rack layout flexibility, restricted forklift access, and reduced the ratio of usable storage volume to gross floor area.

For Phase II (Buildings B4 and B5), the client explicitly sought to overcome traditional column grid limitations and improve storage utilization. After scheme evaluation, BICP proposed a 12 m × 10 m large-span post-tensioned flat slab solution. Using a 3D finite element analysis program imported from the U.S. combined with proprietary post-tensioning optimization algorithms, the design achieved refined analysis of large-span floor loading, confirming feasibility and proceeding to construction.

Technical Challenges

Conventional cold storage facilities typically use 7–9 m column grids due to the mechanical limitations of reinforced concrete slabs: increasing span significantly raises bending moments, and without active compensation, slab thickness and reinforcement ratios escalate rapidly, affecting cost and constructability.

For cold chain logistics operators, this results in: columns occupying usable floor area, restricted rack arrangement options, reduced forklift aisle efficiency, and lower usable storage volume relative to gross area.

Solution

BICP adopted the Taiku large-span post-tensioned flat slab system: post-tensioning tendons are placed within the slab concrete and tensioned to introduce active compressive stress, counteracting bending moments from large spans and enabling 12 m × 10 m column spacing without substantially increasing slab thickness.

Structural analysis utilized a 3D finite element program from the U.S. combined with proprietary optimization algorithms to systematically optimize tendon layout, jacking forces, and anchorage details, controlling material usage while meeting strength and crack control requirements.

The design also accounted for low-temperature effects on concrete shrinkage and long-term prestress losses, incorporating temperature correction factors to ensure stable structural performance over the service life.

Implementation

Post-tensioning construction proceeded in stages, closely coordinated with civil works. BICP's technical team provided on-site supervision, recording threading, tensioning, and locking procedures for each tendon to ensure consistency with design values.

Buildings B4 and B5 were constructed using a flow-line method, with the post-tensioning team working in zones to compress the schedule while maintaining quality.

Delivered Value

Upon completion, the owner compared Phase II (B4, B5) with Phase I. The 12 m × 10 m large-span scheme reduced the number of internal columns by over 60% for the same floor area, increased usable storage volume by approximately 40% (to be confirmed before publication), and significantly improved rack layout flexibility and forklift maneuverability.

Each floor's structural depth was reduced by about 800 mm compared to traditional waffle slab systems, lowering the effective refrigerated volume and positively impacting operational energy consumption.

The project received the First Prize for Scientific and Technological Progress from the China Federation of Logistics & Purchasing and the Sichuan Civil Engineering Li Bing Award, recognizing its engineering value.

Reference Significance

This project is a representative early application of BICP's Taiku system in cold chain warehouses, validating the feasibility of large-span post-tensioned flat slabs for cold storage structures and providing a reference for structural selection in similar future projects.

For investors evaluating large-span schemes during planning, refer to the 'Cold Storage Structural Scheme Preliminary Parameter Comparison' or contact BICP's technical team for preliminary consultation.

Upon completion, the owner compared Phase II (B4, B5) with Phase I. The 12 m × 10 m large-span scheme reduced the number of internal columns by over 60% for the same floor area, increased usable storage volume by approximately 40% (to be confirmed before publication), and significantly improved rack layout flexibility and forklift maneuverability. Each floor's structural depth was reduced by about 800 mm compared to traditional waffle slab systems, lowering the effective refrigerated volume and positively impacting operational energy consumption. The project received the First Prize for Scientific and Technological Progress from the China Federation of Logistics & Purchasing and the Sichuan Civil Engineering Li Bing Award, recognizing its engineering value. This project is a representative early application of BICP's Taiku system in cold chain warehouses, validating the feasibility of large-span post-tensioned flat slabs for cold storage structures and providing a reference for structural selection in similar future projects. For investors evaluating large-span schemes during planning, refer to the 'Cold Storage Structural Scheme Preliminary Parameter Comparison' or contact BICP's technical team for preliminary consultation.