Section 1 General

Article 1. Application

This standard is applicable to steel structures other than those speci­fied in Chapters 1 and 2.

Description:

Steel structures except steel penstocks, hydraulic gates, and trashracks specified in Chapters 1 and 2 should be in accordance with the standards of this chapter. Various articles not specified in this chapter should con­form with the Articles of Chapters 1 and 2, and welding methods and joints should conform with the Articles of Chapters 4 and 5.

Article 2. Definition

Steel structures defined in this chapter are steel linings, hydraulic pres- > sure pipes, waterway conduits, steel surge-tanks including their support­ing structures, and aqueducts, bridges for operating hydraulic gates, gantry cranes and lifting beams.

Description:

Steel linings are lined with steel, used for pressure tunnels,.surge-tanks, etc. to prevent water leakage but which are not subject to stresses from internal pressures. Hydraulic pressure pipes are those filled with water, installed in a waterway, which bear internal pressures by the steel pipe itself, and those embedded in a pressure tunnel which bear internal pres­sure partially or wholly by the steel pipe. Syphon pipes, pipe beams, pipe arches, discharge pipes and pressure pipes on an aqueduct, etc., are in­cluded in the above category. Waterway conduits refer to steel waterways having a free water surface like waterway pipes, and include gutters, open conduits, etc., made of steel.

Section 2 Design

Article 3. Material

1 . Materials to be used for steel structures shall be of types listed in Tables 1.8-1 and 2.10-1, and shall be those materials which have been tested and passed each corresponding standard. Provided sufficient studies were made, materials other than those shown in Tables 1.8-1 and 2.10-1 may be used.

2. Auxiliary facilities closely related to main structures shall be made of steel.

Description:

Those closely related to main structures means the portions constitut­ing critical parts in terms of strength and having great influence on human lives in view of security if damaged.

Article 4. Allowable Stress of Materials

Allowable stresses of materials to be used for design computation shall be in accordance with Article 12., Chapter 1 for steel linings hydraulic pressure pipes, waterway conduits and steel surge-tanks, and Article 12., Chapter 2 for other steel structures.

Description:

Not Applicable.

Article 5. Increase in Allowable Stress

Allowable stresses of materials taking account of seismic load and/or wind load, and allowable stresses of materials for water-filled pipes may be increased by 50% of the values in the preceding Article.

Description:

Since a waterway conduit is under normal load conditions when only partially filled with water, an increase in. allowable stress is not permissi­ble. And, when taking seismic and/or wind loads into consideration, their combined stress should not exceed 90% of a yield point stress.

Article 6. Loads to be Considered

In designing structures, the following shall be taken into consideration

when appropriate; internal pressure, external pressure, the pipe’s own weight, weight of water (including additional weight), seismic load, im­pact load, live load, wind load, snow load, influences of temperature var­iation, etc. .

Description: - ■ '

Wind load, snow load and seismic load should be referred to in Article 13., Chapter I and Article 14., Chapter 2.

Article 7. Combination of Loads

As for loads in the preceding Article when applied to main structures, the following combination shall be taken into consideration;

1. Steel linings

When empty: External pressure

2. Hydraulic pressure pipes

When fully filled with water: Internal pressure, pipe’s own

weight, weight of water in the pipe and temperature variation

When partially filled with water: Pipe's own weight, weight of

water in the pipe and tempera­ture variation

When empty: External pressure

3 . Waterway conduits:

Pipe’s own weight, weight of water in the pipe and temperature var­iation

3. Steel surge-tanks:

Internal pressure, tank’s own weight, weight of water in the tank and wind load

5 . Other steel structures:

Own weight, live load, impact load, water pressure and snow load

For 2. to 5., seismic load, wind load, snow load, etc., shall also be taken into consideration, if required.

Description:

Depending on types and construction of structure, terrain, ground foun­dation, weather, etc. consideration must be taken in combination with the relevant loads mentioned above. As for wind load and seismic load, the larger of the two should be considered in principle. In designing, corresponding items in Chapter 1 and 2 can be applied.

Arch-form waterway conduits in particular should be carefully studied in view of seismic and wind loads normal to a longitudinal direction.

As for a pipe beam structure, attention should be drawn to the fact that the stress in a longitudinal direction at the bottom of the pipe when par­tially filled with water may exceed the stress calculated for a fully filled pipe.