Software Integration Of Safety Analysis Of Reinforced Concrete Structure Considering Temperature During Construction

The reinforced concrete structure during construction is a time-dependent struc-ture which consists of a partly completed structure and a formwork shore system. Ex-perienceshowsthat，astheformworkshoresystemchanges，thetime-dependentstruc-ture may be under the most vulnerable stress state in its”lifetime” and accidents mayoccur. Since1960researchers all over the world have done a lot of researches andexplored some concise and practical calculation methods for construction safety con-trol. P. Grundy and A. Kabaila proposed a simplifed method which is easy to apply.Later in1985Xila Liu presented a three-dimensional fnite element method for struc-tures during construction—a refned method. The simplifed method and the refnedmethod are two ground-breaking methods for analyzing the load transfer in reinforcedconcrete structures during construction.With the development of construction techniques, steel supports are more andmorewidelyusedandgraduallyreplacingtimberingsupports. Experimentshaveshownthat,theefectofexpansionandcontractionofsteelsupportsontheloadtransferduringconstruction caused by daily temperature variation can not be neglected.In order to study infuences of temperature variation on the load transfer, the mainwork can be summarized as follows.At frst, existing structural analysis methods for reinforced concrete frames, slab- column systems, and wall slab structures are unifed based on related researches. Dur-ing analysis, the two-dimensional unsteady heat conduction equation is used to cal-culate the temperature diference between steel shores and concrete columns causedby daily temperature variation, and the efect of temperature variation is considered asa generalized load acting on structures. During analysis, the efects of wood blocksat both ends of steel shore are also considered while calculating the stifness of steelshores.Then a new software named Safety Analysis during Construction consideringTemperature (SACT) is programmed based on proposed structural model and analysismethods. SACT can run under operation systems such as windows2000, windows XP,and windows7, and multiple versions of Excel such as Excel2000, Excel2003, Excel2007, and Excel2010can be used for data input and output. The graphic interfaceis programmed using MFC application. SACT can simulate and calculate structuresduring construction step-by-step. The efect of temperature variation and the infuenceof wood blocks at both ends of steel shores are all taken into account while calculatingthe load transfer by SACT. The software is proved to be accurate and applicable bycomparing with feld test data.Efects of temperature variation on the load transfer during construction are alsodiscussed in the present paper. The load transfer pattern under the infuence of tem-perature is obtained and the critical temperature variation is proposed. If the ambienttemperaturevariationbetweendayandnightislargerthanthecriticaltemperaturevari-ation, the efects of temperature variation can not be neglected.Finally, efectsoftheconstructionperiod, layersofsteelshoresandthestifnessofsupports (the thickness of wood blocks) on the load transfer during construction underthe infuence of temperature are analyzed as well. Based on these analyses, relatedpatterns have been concluded and improvement measures for construction safety areproposed. These conclusions are signifcant for on-site construction personnel.