![]() However, with the use of adequate safety factors, properly located lift-points and appropriate rigging, the out-of-plane bending moments generated during lifting can usually be reduced to acceptable levels to minimize the potential for cracking. Excessive bending stresses can result in horizontal or vertical cracks aligned at architectural reveals or edges of openings. As a precaution, the bond breaker application should always be checked just prior to casting the panels. ![]() These bond forces can develop from an inadequate application of the bond breaker coating on the casting slab, or excessive rain water left standing in the panel openings and reveals without an adequate side draft on at least one edge. As the panel is lifted from the casting slab, over 1g of force can develop normal to the wall’s surface due to dynamic forces or bonding to the casting slab. In some respects, the concrete wall panels experience the greatest potential for cracking as they are being tilted from horizontal to vertical while being erected. The lifting and setting of wall panels, as well as the effects of restrained drying shrinkage, are important items to address to minimize potential wall cracking. While many of the features of tilt-up panel construction tend to reduce the potential for developing cracks when compared to conventional concrete construction, the unique method of how the buildings are constructed still requires some special considerations for controlling cracking. Single story occupancies are still most common however, many buildings are now multiple stories. The individual wall panels are erected around the building’s perimeter, separated by vertical joints. ![]() Tilt-up concrete construction incorporates concrete wall panels that are formed, cast and cured on a ground supported slab at the building site and then tilted into place, one large panel at a time. ![]() With newer types of occupancies driving attention to aesthetics higher and higher, the importance of minimizing concrete cracking in the site-cast precast wall panels is greater than ever. Long considered the mainstay for warehouses and big-box retail, the tilt-up method is now frequently employed for commercial projects, churches, schools and Class A office buildings nationwide. When it comes to enclosing large building volumes, it is hard to beat tilt-up concrete construction for economy and durability. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |