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STANDARD SPECIFICATIONS FOR BUILDING WORKS (JKR)

(2005 Edition)

 

5.         Ceiling Suspension System

5.1        General

5.1.1     Where shown in the Drawings, ceiling suspension system shall consist of metal members comprising main tees, cross tees, wall angles and hanger wires complete with hanger jackets and clips, designed to support the suspended ceiling, light fixtures and/or air diffusers with a maximum deflection of 1/360 span.

5.1.2     Unless otherwise specified, all exposed members of the suspension system shall be of colour to match that of ceiling tiles, to the approval of the S.O.

5.2        Design Considerations

5.2.1     The width of all main tees and cross tees with double-web design shall be 24mm. Wall angles shall be of the same width as the exposed tees.

5.2.2     Hanger wires shall be galvanised carbon steel, soft tempered, pre-stretched with a yield stress load of at least three (3) times the design load, but in any case shall not be less than 12 gauge (12.6 mm) diameter. Thicker gauge wire shall be used for heavier load carrying installation or in situations where the hanger wires spacing exceeds 1200mm centre to centre.

 

American Society of Civil Engineers

ASCE 7-02

Minimum Design Loads for Buildings and Other Structures

9.6.2.6.1    Seismic Forces. Suspended ceilings shall be designed to meet the force requirements of  Section 9.6.1.3.

The weight of the ceiling, Wp , shall include the ceiling grid and panels; light fixtures if attached to, clipped to, or laterally supported by the ceiling grid; and other components which are laterally supported by the ceiling. Wp shall be taken as not less than 4 Ibs/ft2 (19 N/m2).

Ulasan

1.    Perkara 5.2.2 dalam spesifikasi JKR, saiz 12 gauge itu sepatutnya 2.6mm dan bukannya 12.6mm.

2.    Siling runtuh bermaksud siling sahaja yang runtuh, dan kekuda bumbung masih stabil.

3.    Jika siling runtuh bersama dengan kekuda bumbung, bermaksud kekuda bumbung yang gagal.

4.    Contoh kiraan beban suspended siling berdasarkan ASCE 7-02. 

5.    Design load = 4  Ibs x 4’ x 4’ = 64 Ibs per ceiling wire = 29 kg per ceiling wire

6.    Yield stress load of at least three (3) times the design load

a.    Design load                          = 29 kg

b.    3 times the design load      = 3 x 29 kg = 87 kg

c.    Yield load                               = approximate 0.87 x 87 kg = 76 kg

7.    Ceiling wire yang ingin digunakan, perlu dibuat “tensile test”. Kekuatan wire (tensile strength) adalah berbeza daripada setiap pengeluar. Oleh yang demikian adalah sangat penting tensile test  dijalankan.

             a.    Lihat graf yang diplot dan lihat titik (point) yield dan bukan beban maksima dan bukan beban semasa wire putus.

b.    Rujuk beban pada graf pada titik (point) yield tersebut.

c.    Bandingkan beban tersebut dan hendaklah melebihi 76 kg atau 0.745 kN. Ini bermaksud rekabentuk dibuat supaya ceiling wire yang digunakan dalam keadaan sentiasa elastik.

 

8.    Selain tensile test dijalankan, terdapat perkara-perkara lain yang perlu dilihat, antaranya ialah:

a.    Beban tambahan baru selepas bangunan diserahkan (i.e tambahan wayar ICT di atas siling). Perlu maklum kepada pelanggan supaya tidak menukar suspended ceiling kepada plaster ceiling, kecuali direkabentuk semula.

b.    Jarak antara ceiling wire melebihi 1.2m antara satu sama lain.

c.    Penggunaan "anchored attachment" ke dalam concrete slab tidak dibuat "pull-out test"

d.    Ceiling wire yang condong – secara amnya perlukan dua ceiling wire kerana stress yang tinggi pada wire condong berbanding ceiling wire yang tegak.  

e.    Sebelum handing over, pemeriksaan dijalankan pada setiap pemasangan peralatan elektrik dan memastikan peralatan tersebut digantung berasingan.  

 

 

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