At present, dampers are widely used in the field of energy dissipation in engineering structures. However, when the displacement and velocity output of dampers are not significant under small and medium-sized earthquakes, it is difficult for a damper to fully exert its energy dissipation capacity. The use of toggle-brace mechanisms in the structure is an effective method to solve the above problems, and the effect of toggle-brace-viscous dampers (referred to as TBVDs) in the structure can be reflected by a magnification factor (referred to as M_f). Therefore, it is particularly important to study the calculation method for the M_f of TBVD. Domestic and foreign scholars have achieved certain results in the study of the calculation method for the M_f of TBVD, and the corresponding calculation formula for the M_f has been proposed. Given the existing research results, this article conducts the following work: analyzing the shortcomings of existing methods for calculating the M_f of TBVD, proposing an improved method for calculating the M_f of viscous dampers, comparing the accuracy of existing and improved algorithms, and analyzing the calculation results to provide practical suggestions for engineering applications.

The research work herein presented is aimed at investigating the effects of different influencing factors on the in-plane failure mode of unreinforced masonry (URM) structures. Firstly, the in-plane stress failure criterion cited in this paper was introduced, and the corresponding judgment procedure was demonstrated. Then, various finite element models considering different influencing factors were established, which included the aspect ratio of pier (η), stiffness ratio of pier to spandrel (ρ) and vertical load (σ). Furthermore, the in-plane stress failure criterion that we introduced was used to evaluate the failure modes of each model. The main findings of the simulations were as follows: under the condition of (η ≤ 1.0), three failure modes emerged in all models, which included pier, mixed and spandrel failure modes, with the gradual increase in ρ. Once the value of η exceeded 1.0, all models exhibited the pier failure mode regardless of whether the value of ρ increased or decreased. Moreover, under the identical aspect ratio (η = 1.0), the failure modes of the models altered regularly with the increase in the value of σ (from 0.3 MPa to 0.6 MPa), which transferred from pier failure to mixed failure, and from mixed failure to spandrel failure. The research results not only provide theoretical reference for the design of new masonry buildings, but also provide technical guidance for the judgement and prediction of failure modes of existing masonry buildings.

With the increasing emphasis on sustainability, more and more environmentally friendly new materials and structures are developed, but they are difficult to be applied in engineering practice due to the lack of mature force resistance models. The design assisted by the testing method proposed by ISO2394:2015 and EN1990:2002 can solve this problem effectively. The aim of this paper was to analyze the characteristics of the method from a mathematical and statistical point of view based on the data and to suggest improvements. The resistance of each concrete member was derived by the design assisted by testing methods. The derivation results showed that the values, the number of tests , the coefficient of variation , and the coefficient of variation of resistance known or unknown have a large impact on the derived results. Also, the derivation by the Bayesian procedure or interval estimation methods might be negative. This indicates that the theory of the method is not rigorous and has some disadvantages.