Load monitoring and hazard warning systems for buildings under construction

The construction phase of a building is one in which the structure is rather vulnerable to damage and/or collapse. The potential for human and economic loss, as well as the potential for reduced construction costs, presents an opportunity for developing construction structural load and response monitoring systems that can possibly be effective in reducing the frequency of collapses and/or damage. This paper presents the results of a study in which such systems were developed and applied to slab-style concrete building construction. The shoring systems that are used to support fresh concrete floor slabs are instrumented with strain gage based load cells to measure the loads during construction operations. The loads on the shores have been measured during the construction of three different buildings. This information is being used for construction procedure code development. The next phase of this research is to apply the sensing system so that it can provide an early warning for potential collapses of the partially- built structure. Mechanical models of the structural system indicate that load monitoring of individual shoring members is probably insufficient because the major structural collapses are due to a global instability. It appears that a combination of strategically-placed load, temperature and deflection monitoring instrumentation combined with a real-time analysis of the data may be necessary. The design and use of such systems are discussed.