Prefabricated Houses in Zhangye
In Zhangye, prefabricated houses are mainly old-style prefabricated panel buildings, which have issues such as numerous roof joint gaps, outdated drainage systems, and weak resistance to freezing and aging. House inspections should focus on the length of the connection between the floor slab and the wall, as well as the cracking patterns of the walls.
The old-style prefabricated panel buildings in Zhangye are mostly concentrated in the core area of Ganzhou District. The roofs of these buildings are assembled from prefabricated concrete panels, resulting in numerous joint gaps. Additionally, the gutter drainage systems often suffer from blockages due to their age. Affected by the local climate, these buildings have weak resistance to freezing and aging. Freeze-thaw cycles can easily cause concrete cracking. During heavy rain, the roofs are prone to seepage, and during the snowmelt period, leaks may occur due to poor drainage. These issues occur frequently throughout the year, affecting living safety and comfort.
From the perspective of building inspection technology, the length of the connection between the prefabricated concrete hollow panel floor slab and the load-bearing wall is a key indicator. According to design specifications, such connection lengths are typically required to be between 80 and 120 millimeters. However, in actual inspections, it has been found that when the walls develop vertical cracks or horizontal mortar joint compression deformations due to mortar aging, the support area of the hollow panels decreases, leading to local compressive stresses exceeding design limits. For example, if wall deformation reduces the connection length below the minimum allowable design value, the load transfer path of the floor will deviate from the original design. The upper loads may be forced to transfer to adjacent ring beams or structural columns, causing these secondary components to bear stresses beyond expectations. Long-term accumulation of such stresses may lead to structural safety hazards.
During the inspection process, laser rangefinders should be used to verify the connection dimensions, and crack width gauges should be employed to record the cracking patterns of the walls, thereby establishing the current geometric boundary conditions of the components. If insufficient connection lengths or abnormal wall cracking patterns (such as continuously widening cracks or dense distributions) are detected, further structural safety assessments are necessary. If required, reinforcement measures should be taken, such as adding support points, repairing wall cracks, or updating the drainage system, to enhance the building's resistance to freezing and seepage and extend its service life.
