SU1738950A1 - Metal-wooden structure support unit - Google Patents

Abstract

Usage: in units of supporting structures made of glued wooden elements. SUMMARY OF THE INVENTION: The support assembly includes a glued wood element, a taper and a thrust traverse placed in a vertical undercut of the wood element. The trimming is designed as a cantilever protrusion with a given length, the minimum length of which is determined by the formula. 1 il.

Description

The invention relates to construction and is intended for the manufacture of load-bearing structures consisting of glued wood elements.

The aim of the invention is to increase reliability by creating clamping forces across the fibers and reducing material consumption.

The drawing shows the support unit of the metal-drift structure.

The assembly includes glued wood element 1. thrust traverse 2, fastening elements 3, trimming 4 wooden elements in a vertical plane, cantilever protrusion 5 and horizontal supporting plane 6.

When a wood element is loaded in puffing 3, a tensile force occurs, which is transmitted through the resistant cross member 2 and undercut 4 to the wood element 1. The reactive forces in the horizontal support plane 6 create a bending moment in the cantilever protrusion 5, by which the breaking stress across the fibers from the eccentric action of the force N. The normal force N is applied with an eccentricity e. The value of which in known solutions can be no more than 1/6 of the height of the cross section due to the appearance of forces across fibers that exceed design values.

In this solution, there are no restrictions on the eccentricity due to the creation of a bending moment on the cantilever protrusion, from which compressive forces arise across the fibers, partially or fully compensating for the tensile stresses across the fibers from the application of compressive force N. This will increase operational reliability and reduce material intensity of the structure.

As an example of a specific implementation, consider a triangular three-ball peaceful arch span of 18 m under a load of 1200 kg / m. For this design, the cross section of the wood element is

cl

with

% |

with

O) o

sl o

140 x 660 mm 9 (h) LN 18.753, that is, 0.1 m “1 / 6h. , 714 kg / cm2. For this node e 1 / 3h "0.19 ti, the length of the protrusion is equal to

a | GZh753 (6XHS-66T „29cm 3X25.714X14

The height of the lower cantilever protrusion is obtained at a value of the calculated resistance of wood to bending at an angle to the fiber direction Rud ° 90 kg / cm2 equal to 0.27 m. The cross section of the wood element is 140 x 610 mm. The wood consumption reduction is 7.6%.

The formula for determining the length of the cantilever protrusion is derived from the following hypotheses. Under a horizontal bearing pad, the stresses are uniform across the entire plane; the maximum permissible value of the eccentricity of applying a normal force in the supporting node of known solutions is h / b.

Uniformly distributed stresses with a cantilever width b and a length a give a bending moment

a x h x a2

N (e - h / 6 |

(3)

From the last formula get the desired value of the length of the cantilever protrusion

, W m (ve - yyyy Y 3Xffkb

(four)

Claims (1)

This constructive solution in comparison with the prototype - arch by cipher 37TS-89 - allows to obtain the economic effect of the conditional implementation of the node e 1000 structures in the amount of 47.5 thousand rubles. Claims Anchor unit of metal-wood construction, including a wood glued element, a taper and a thrust traverse placed in a vertical undercut of a wood element, characterized in that, in order to increase reliability by creating clamping forces across the fibers and reducing material intensity, trimming made in the form of a console protrusion of length a, determined from the following ratio Mk a X b X a (one) Accepting the value of eccentricity in the proposed solution e 5 - “-, you can get the value of the bending moment outside e h / 6. Me - N. {e - h / 6). (2) Moments Mk and Me must be mutually balanced, which allows you to write a | (be-PG - T where N is the compressive force at the support node; .e - eccentricity of application of compressive force; h is the height of the cross section of the wood element; a - tightly under a horizontal support platform; b is the width of the cross section of the wood element.