Observations from Shore Load Measurements during Concrete Construction

Loads during construction are highly variable and are often far in excess of what might be considered reasonable for purposes of design. While formwork design is still generally the responsibility of the contractor, increased attention is being paid to the engineered design of these and other temporary support systems. The relative frequency of failures of structures during construction versus those during service suggest that an engineered approach to formwork design in certain construction situations may be warranted. In this paper, initial observations from actual shore load measurements are made and the implications for design and construction are discussed. Specific attention is paid to the shore load effect (i.e., that value of load to which the shoring element is actually subjected). The work reported in this paper is part of an ongoing project to develop recommendations for design during construction. The qualitative analysis described herein provides much needed information on the magnitude and variations in load effect. In addition, this information can be used to relate the applied loading (i.e., actual loads on the slab) to the shore load effect, thereby providing information on load-structure interaction that may be important for safe design and construction of formwork systems.