1917 (#619-628) - Laserfiche WebLink

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18l feet smd the number of stories shall not exceed four exclusive of basement. Class "D" buildings shall include all buildings not of class "A" 'B" "C" construction and must not exceed three stories or 40 feet in height. Section 13. Claes "A" or fireproof buildings must meet the following minimum requirements: Exterior walls built as filler walls, that is walls which are carried at every story by means of fireproof construction shall be not less than 4 inches thick of re-inforced concrete and not less than 8 inches thick for other masonry. Interior court walls not less than 3 inches thick if of reinforced concrete or 6 inches thick of other masonry. Ail hollow partitions or interior permanent partitions shall be built of fireproof material. All wood trim must be backed solidly. Where skeleton steel construction is used cast iron columns may be used where height of building does not Sxceed 5 stories. Where cast iron wrought iron, or steel columns are used they must be protected by masonry casing not ].ess than 3 inches in thickness on allsides, unless concrete is used in which case the minimum thickness shall be used. Where in casing masonry is other than concrete there shall be a space of not less than one inch left between the masonry and the column, which space shall be filled solidly with liquid cement grout as the courses are laid up. This inch may be figured as part of the thickness of the casing, where masonry of any description is used it must be thoroughly bonded together with metal rods or wire. Wrought iron or steel girders in outside walls shall be similarly covered with masonry tied and bonded but the extreme outer edges of the flanges or beams and plates or angles connected to the beams may project to within one inch of the outside surfaces of the masonry casing. A facing of granite, marble or other stone which i~sub- Ject to disintegration by heat shall not be considered as fire- proofing. In no case shall a granite or marble column be used to carry a wall exceeding one story in height. No pipes, electrical wires or conduit of any kind shall be encased in the fire-proofing surrounding any column, girder or beam of steel or iron but shall be placed outside of such fireproofing. Where the fireproof protection of columns may be exposed to damage from trucking or handling of merchandise, such fireproof protection shall be jacketed on the outside for a height not less than 4 feet, either with heavy sheet metal or hard wood str~ps not less than 2 inches thick. All exposed sides of iron or steel beams used to carry any portion of the load in the building shall be entirely encased as specified above for beams and columns. The filling between beams of fireproof floors when other thau a re-inforced concrete must correspond to the requirements of the building code of the National Board of Fire Underwriters as required in the edition of 1909. Section 14. Re-inforoed concrete construction when used in any building must meet the following minimum requirements; reinforced concrete shall be considered class "A" construction provided that the minimum thickness of concrete surrounding re- inforced members of columns shall be two inches, of girders and beams 1½ inches,of floor slabs 1 inch. D~&wings for re-inforced concrete buildings must specify the details of the re-inforcem%nt. In calculating the strength of the different parts of re-inferced concrete structures the following limitations must be observed. The size of columns, girders or bemms to be taken to the outside of the reinforcing material only. Concrete outside of re-inforcing materials to be considered as fireproofing only except in partitions which carry no loads, on which there shall be no such limitations. In isolated beams where steel is figured to develop full strength, the area of tensile reinforcement must not exceed one per cent of sectional area of beam, excepting that excess tensile re-inforcement may be allowed if compressive re-inforcement equal to 14 times the excess area of tensile reinforcement used. ~he following shall be the minimum requirements: Maximum allowable fibre stress in steel 16, OO0 pounds per square inch. Maximum shearing stress On concrete 50 pounds per square inch. Maximum direct compression allowed on concrete 500 lbs. per square inch, except in hooped columns where ?50 lbs. will be allowed. Maximum shearing stress in steel lO,COO lbs. per square inch. Adhesion of steel to concrete plain bars 50 lbs. per square inch of surface of bar, deformed bar 75 lbs. Ratio of moduli of elasti- city of steel to concrete 15 to 1. Design for reinforced concrete construction must conform to standard engineering practice and special care must be taken to see that proper precautions are followed when pouring to prevent weakening the structure. In no case must forms or supports be moved before the cement is properly set and not within 14 days in the case of slabs, beams and columns. The building inspector shall have authority to compel proper precautions being taken to insure correct casting, but this section shall not be construed as holding the building inspector or the City liable for defective construction. The contractor must be prepared to make load tests of twice the intended safe load if required by the building inspector on any portion of re-inforced concrete or steel constructed build- ing 30 days after such portion has been erected, and the parts es tested must not shew a deflection of more than 1/~00 of the clear span. All cement used in reinforced concrete work must be tested by a responsible tester. The building inspector may if he wishes, accept manufacturers' tests. All of these tests to meet the re- quirements specified by the American Society for Testing Materials.