A simplified 3D multi-degree-of-freedom (MDOF) model for estimation of seismic response of reinforced concrete wall-frame structures with uniform stiffness along the height are proposed in this paper. This model is aimed at reducing the computation demand in the nonlinear response history analysis (RHA). By employing the continuum technique for the structure and adopting the bilinear hysteretic model for material properties, the procedure for the development of a simplified MDOF model, called continuum MDOF model is developed. The proposed continuum MDOF model is shown to provide a simple and efficient for computation of nonlinear response of tall wall-frame structures.

BackgroundRequirements of blood transfusions rise rapidly in China. Improving the efficiency of blood donation could help maintaining sufficient blood supplement. We conducted a pilot research to investigate the reliability and safety of collecting more units of red blood cell by apheresis.MethodsThirty‐two healthy male volunteers were randomized into two groups: red blood cell apheresis (RA) (n = 16) and whole blood (WB) donation (n = 16). RA group donated individualized RBC volumes by apheresis according to the volunteers' basal total blood volumes and haematocrit levels, WB group donated 400 mL whole blood. All volunteers were scheduled seven visit times in 8 weeks' study period. The cardiovascular functions were assessed by laboratory examinations, echocardiography and cardiopulmonary functional tests. All results were compared between groups at the same visit time and compared between visit 1(before donation) and other visit times within the same group.ResultsThe average donated RBC volume in RA group and in WB group was 627.25 ± 109.74 mL and 175.28 ± 8.85 mL, respectively(p < 0.05); the RBC, haemoglobin and haematocrit levels changed significantly between times and between groups (p < 0.05). Cardiac biomarker levels such as NT‐proBNP, hs‐TnT and CK‐MB did not change significantly between times or between groups (p > 0.05). The echocardiographic and cardiopulmonary results did not change significantly between times or between groups during the whole study period(p > 0.05).ConclusionsWe provided an efficient and secure method for RBC apheresis. By harvesting more RBC volumes at one single‐time, the cardiovascular functions did not change significantly compared with traditional whole blood donation.

To understand the higher modal effect on the accuracy of pushover analysis for shear wall structure, the influence of damage on the vibration characteristics of shear-wall structures is investigated. Employing the continuum technique, the shift of modal shapes and periods for the first three modes is obtained when the plastic zone exists in the bottom of the shear wall. It can be conclude that plastic zone may enhance the higher modal effect when the internal force responses of shear walls are considered. The higher modal contribution can not be neglected when computing the nonlinear earthquake responses of shear wall structures.