IMPROVING EARTHQUAKE RESISTANCE OF SMALL BUILDINGS BASICS AND TUTORIALS

IMPROVING EARTHQUAKE RESISTANCE OF SMALL BUILDINGS BASIC INFORMATION
How To Improve The Earthquake Resistance of Small Buildings?


1. Site Selection: 
The building constructions should be avoided on
(a) Near unstable embankments
(b) On sloping ground with columns of different heights
(c) Flood affected areas
(d) On subsoil with marked discontinuity like rock in some portion and soil in some portion.

2. Building Planning: 
Symmetric plans are safer compared to unsymmetric. Hence go for square or rectangular plans rather than L, E, H, T shaped. Rectangular plans should not have length more than twice the width.

3. Foundations:
Width of foundation should not be less than 750 mm for single storey building and not less than 900 mm for storeyed buildings. Depth of foundation should not be less than 1.0 m for soft soil and 0.45 m for rocky ground.

Before foundation is laid remove all loose materials including water from the trench and compact the bottom. After foundation is laid back-fill the foundation properly and compact.

4. Masonry: 
In case of stone masonry:
• Place each stone flat on its broadest face.
• Place length of stones into the thickness of wall to ensure interlocking inside and outside faces of the wall.
• Fill the voids using small chips of the stones with minimum possible mortar.
• Break the stone to make it angular so that it has no rounded face.
• At every 600 to 750 mm distance use through stones.

In case of brick masonry:
• Use properly burnt bricks only.
• Place bricks with its groove mark facing up to ensure better bond with next course.

In case of concrete blocks:
• Place rough faces towards top and bottom to get good bond.
• Blocks should be strong.
• Brush the top and bottom faces before laying.

In general walls of more than 450 mm should be avoided. Length of wall should be restricted to 6 m. Cross walls make the masonry stronger. It is better to build partition walls along main walls interlinking the two.

STEEL FABRICATION PROCESSES BASICS AND TUTORIALS

STEEL FABRICATION BASIC PROCESSES
What Is Steel Fabrication?

When considering fabrication, as well as erection of the fabricated product, the designer must taken into account contractual matters, work by others on the construction team, schedule implications of the design, and quality assurance matters.

Fortunately, there are well established aids for these considerations. Contractual questions such as what constitutes structural steel, procedures for preparing and approving the shop detail drawings, and standard fabrication procedures and tolerances are all addressed in the AISC’s Code of Standard Practice.

Insights on economical connection details and the impact of material selection on mill material deliveries are generally available from the fabricator’s engineering staff. These engineers are also able to comment on unique erection questions.

Quality assurance questions fall into two categories, fabrication operations and field operations. Today, sound quality control procedures are in place in most fabrication shops through an AISC program which prequalifies fabricators.

There are three levels of qualification: I, II and III, with Level III being the most demanding. Fabricators with either a Level I or Level II certification are suitable for almost all building work. Most engineers incorporate the AISC’s Code of Standard Practice in their project specification.

Shop Detail Drawings

Detail drawings are prepared by the fabricator to delineate to his work force the fabrication requirements. Because each shop has certain differences in equipment and/or procedures, the fabricator develops details which, when matched with his processes, are the most economical.

To accomplish this end, the design drawings need to be complete, showing all structural steel requirements, and should include design information on the forces acting at connections.

Designers should avoid specifying deck openings and beam penetrations through notes on the drawings. This is a frequent cause of extra costs on fabrication contracts.

Fabrication Processes

Mill material is cut to length by sawing, shearing, or flame cutting. Columns may also be milled to their final length. Holes for fasteners are drilled or punched.

Punched and reamed holes are seldom used in building construction. Cuts for weld preparation, web openings, and dimensional clearances are flame cut. AISC guidelines for each of these processes are associated with the AISC’s fabricator prequalification program.

Welding for building construction is performed in accordance with the provisions of the AWS Structural Welding Code, D1.1. Most requirements can be satisfied using pre-qualified welding procedures.