scholarly journals Analysis of the stress state at the double-step joint in heavy timber structures

2019 ◽  
Vol 69 (335) ◽  
pp. 196
Author(s):  
J. R. Villar-García ◽  
P. Vidal-López ◽  
J. Crespo ◽  
M. Guaita

The double-step joint is among the most frequently used layouts, within carpentry joints, for transmitting higher forces that would allow a single notch. They are especially effective in heavy timber structures. Nowadays, computer-aided manufacturing is being used more often, demanding further progress in its understanding. The conventional design of these joints is conducted by using simplifying assumptions, in particular regarding the shear stress distribution. This is overcome by the use of strength reduction coefficient, which is currently under study. Numerical simulation and experimental tests were carried out with heavy timber cross-sections for rafter to tie-beam truss joint. They were manufactured in glue-laminated timber owing to the large cross-sections tested. Experimental load-strain and load-displacement diagrams were compared with numerical results. This allowed observing the great shear stress concentration produced in the failure by shear crack, which suggests the application of conservative shear strength reduction coefficients.

2009 ◽  
Vol 1 (3) ◽  
pp. 148-156 ◽  
Author(s):  
Zoja Bednarek ◽  
Mečislavas Griškevičius ◽  
Gintas Šaučiuvėnas

The present research was dedicated to investigation into the strength of timber structures under fire conditions. Two kinds of timber specimens including oak and pine were used. The carried out investigation covered static tests on tensile strength, compressive strength along the grain, compressive strength perpendicular to the grain and flexural strength. The specimens were tested under the temperatures of 50°C, 100°C, 150°C, 200°C and 230°C. The obtained results show that pine specimens have better properties over the entire temperature range in case of tests on tensile and flexural strength. Also, as for these types of strength, oak specimens show a higher strength reduction rate than those of pine specimens, whereas oak specimens have better properties over the entire temperature ranges in case of compressive strength perpendicular to the grain. Based on statistical analysis, a linear expression of the strength reduction coefficient was proposed.


2012 ◽  
Vol 204-208 ◽  
pp. 241-245
Author(s):  
Yang Jin

The stability of soil slope under seepage is calculated and analyzed by using finite element method based on the technique of shear strength reduction. When the condition of seepage or not is considered respectively, the critical failure state of slopes and corresponding safety coefficients can be determined by the numerical analysis and calculation. Besides, through analyzing and comparing the calculation results, it shows that seepage has a negative impact on slope stability.


2021 ◽  
Vol 180 ◽  
pp. 106583
Author(s):  
Wei Xing ◽  
Li Gang ◽  
Xiao Lin ◽  
Zhou Linjun ◽  
He Ke ◽  
...  

2011 ◽  
Vol 243-249 ◽  
pp. 1279-1282
Author(s):  
Li Hong Chen ◽  
Shu Yu ◽  
Hong Tao Zhang

Shear strength reduction finite element method (SSRFEM) has been a main technique for stability analysis of slope. Although SSRFEM has advantages to deal with complex geometry and nonlinear material, the criteria for failure is still argued. Ideal elastoplastic model and rheological model were both adopted, and the results of computation showed that using the intersection of two straight lines as failure point was more appropriate. The usage and advantage of two different material models was compared.


2012 ◽  
Vol 594-597 ◽  
pp. 222-225
Author(s):  
Wen Juan Feng ◽  
Xiao Dong Ju ◽  
Zheng Sheng Zou

Although anti-slide pile take a key position in slope-treating measures, the method of designing is far from perfect. The methods used in actual projects are based on the rigid body limit equilibrium methods. There is a tendency to using numerical methods in the progress of pile-designing. The safety factor of landslide is calculated according to shear strength reduction theory in the numerical simulation software. Using the shearing forces on pile and the safety factor can ascertain the position of anti-slide piles, the area and distance of piles. For numerical simulation can well perform the simulation slope moving and the load on piles and can give a more reasonable designing.


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