Estudio crítico del cálculo de flechas en vigas de hormigón armado según la instrucción EH-88

Critical study of the evaluation of deflection in reinforced concrete beams according to Spanish Code EH-88

The new spanish concrete code EH-88 establishes a simplified method to calculate deflections in R.C. flexural members, non-existent in old EH-82 code. Criteria and methodology assumed for calculations of instantaneous deflections are appropiate and provide adjusted results. Nevertheless, the over-simplified method proposed to evaluate long-time deflections supplies very conservative resluts, comparatively with international european concrete codes (EC-2, CEB-FIP Model Code), and with main analytical models. In this work a comparative study of most relevant models to calculate deflections in RC flexural members is presented. Also, a systematic comparison of deflections in RC building beams calculated according to EG-88 simplified method and EC-2 general model is shown. It proves the inadequcy of spanish concrete code in this matter, and shows its practical consequences in the design of concrete building frames. In the same issue, authors propose an alternative simplified method to calculate long-time deflections in RC flexural members.