Load Bearing Walls: Construction & Design Essentials

1. English for Building and Construction Engineering Unit Six Part Two Load Bearing Walls

2. Learning Objectives After learning this section, you will be able to know some professional words and expressions; explain the construction of load bearing walls; Know about lateral loads and vertical loads on load-bearing walls; practice your reading skills;

3. Lead-in • What is the difference between load bearing wall and non-load bearing wall? • What loads should load bearing wall carry?

4. What is load bearing walls? • Walls that carry a weight other than their own are known as load bearing walls.

5. Crucial Factors for Designing A Load Bearing Wall • the condition of loading • the conditions of the vertical and lateral support • the allowable stresses (or load factor) • whether there are any doors, windows or other openings in the wall.

6. The effect of opening • The size of the opening affects the strength of a wall. • A small one has little effect but a big one has great effect on the strength of the wall.

7. What will affect the stability of a Masonry wall? • dead loads • live loads • long term dimensional changes of brickwork • movement of structural members • foundation movement.

8. What loads will load bearing walls carry? According to the direction: • Lateral loads • Vertical loads

9. Lateral loads on walls Things to be kept in mind when constructing lightly loaded buildings: • wind load is quite essential. • The main consideration is to stop the wall from overturning

10. Lateral loads on walls Ways to prevent the overturing failure caused by wind are: • providing intersecting walls, • anchoring timber framed roofs against uplift, which also provides lateral support.

11. Lateral loads on walls Features of long walls under lateral loads: • Long walls may fail under lateral loads by the bricks turning on their bed joints. • Bond strength is often more important than crushing strength for long walls.

12. Vertical loads on walls Vertical loads on tall thin masonry walls: • Tall thin masonry walls tested under eccentric or off centre loads will generally fail by buckling (变形，弯曲).

13. Vertical loads on walls To prevent the buckling, it depends on: • the distance between end returns, • properly bonded cross walls, • the amount of lateral support a wall receives from floor and roof systems.

14. Load bearing walls construction Major points about load bearing walls construction: • Brickwork should be laid accurately, plumb and bonded. • Bed joints (horizontal) and perpend joints (vertical) are not to exceed 10mm in thickness. • Bricks should be laid on a full bed of mortar with perpend joints completely filled.

15. Load bearing walls construction Major points about load bearing walls construction: • Before commencing brickwork, the bricklayer should be informed by the builder / supervisor of the position of all damp-proof material and flashings. • On completion of bricklaying, all mortar splashes and stains should be removed and the brickwork left in a clean finished condition.