With a partial safety factor ? = 1.25, the design shear stress should be limited to 12MPa (=15/1.25MPa).Together with cancer the increase in beam strength, the beam rotation corresponding to the maximum loads increased steadily from about 0.01 Rad with 1% wall reinforcement to about 0.02 Rad with 3.5% wall reinforcement. Such a relatively large beam rotation may be too high for the building subjected to ultimate wind loading conditions.4. Conclusions By employing a nonlinear finite element analysis that has been validated by the results of a previous experimental study, the effects of beam geometries and anchorage arrangements on the overall performances of PRC coupling beams have been studied numerically and presented in this paper. The findings from the parametric study are summarized as follows.

PRC coupling beams would be most effective with a span-to-depth ratio of about 2 under various longitudinal steel ratios.The critical regions (above and below the plate anchors near the beam-wall joints and at the ends of the plate anchors), which are prone to cracking in the wall piers, have been identified.Insufficient plate anchorage length would result in a reduction of beam strength and stiffness, but an increase of the anchorage length beyond the minimum required value for full capacity development would not further improve the beam performance much. A parabolic La/l�Ch/l relationship is recommended for determination of the anchorage length.Apart from insufficient plate anchorage length, insufficient wall reinforcement could also result in premature beam failure.

However, the required wall reinforcement ratio could be far exceeding the practical limit in PRC coupling beams designed for extremely large shear stresses. The maximum allowable shear stress should therefore be limited to 15MPa. In practice, it is more desirable for the plate to share about 50% of the total load resistance.The results in the present study have enhanced the development of a comprehensive design procedure for the PRC coupling beams [18].AcknowledgmentThe work described in this paper has been fully supported by the Research Grants Council of Hong Kong SAR (Project nos. HKU7129/03E and HKU7168/06E).
In the problem of testing a statistical hypothesis H0, a frequentist may give evidence against H0 by the observed significance level, the P value, while a Bayesian may give it by the posterior probability that H0 is true. Lindley [1] illustrated the possible discrepancy between the Bayesian and the frequentist evidence. The relationship of these two measures of evidence is then extensively studied in the literature. AV-951 Pratt [2] revealed that the P values are usually approximately equal to the posterior probabilities in the one-sided testing problems.