Page 58 - Building Regulation and Design Guidelines - Structural (Grey Code)
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SECTION: 4  STRUCTURAL DESIGN GUIDELINES - STEEL STRUCTURES                           SECTION: 4  STRUCTURAL DESIGN GUIDELINES - STEEL STRUCTURES






                            Loading                                Factor, f
                                                                                                           Cantilevers                             Length/180
                            Dead load                               1.4                                                                            Span/360
                            Dead load restraining uplift or overturning  1.0                               Other beams (except) purlins and sheeting rails  Span/200
                            Dead load acting with wind and imposed                                         Purlins and sheeting rails              See 4.12.2
                                 loads combined                     1.2
                            Imposed load                            1.6                                    Tops of coloumns in single-storey building, except portal frames  Height/300
                            Imposed load acting with wind load      1.2                                    Coloumns in portal frame buildings, not supporting crane runways  To suit cladding
                            Wind load                               1.4                                    Coloumns supporting crane runways       To suit crane runway
                            Wind load acting with imposed load or                                          In each storey of a  builidng with more thean one storey  Height of that storey/300
                                 crane load                         1.2                                    c) Crane girders
                                                                    1.2                                                                            Span/600
                                                                                                           from overhead travelling cranes
                                                                                                                                                   Span/500
                            Vertical load                           1.6                                    properties alone) due to horizontal crane loads
                            Vertical load acting with horizonal loads                                                   Table 4.2.  Deflection Limitations - BS 5950
                                 (crabbing or surge)                1.4
                            Horizontal load                         1.6                                         3.   When checking for deflections the most adverse realistic
                            Horizontal load acting with vertical    1.4                                              combination and arrangement of serviceability loads shall
                                                                                                                     be  considered,  and  the  structure  may be assumed to behave
                            Crane load acting with wind load*       1.2
                                                                                                                     elastically. On low pitched and flat roofs the possibility of ponding
                                                                                                                     should be investigated.
                            * When considering wind or imposed load and crane loading
                                                f
                            acting together the value of        for dead load may be taken as 1.2.              4.   Vertical and horizontal limits of deflection due to all loads shall in
                                                                                                                     general be limited to the deflection limits specified in the codes.
                                                                                                                     Special care shall be taken to limit the deflection to suit the
                                                                                                                     cladding, crane girder tolerances, members supporting sensitive
                               Table 4.1.  Load Factors and Combinations - BS 5950
                                                                                                                     machineries etc.
                                                                                                                5.   Floor vibrations  shall satisfy the  criteria recommended by AISC
                    4.3.4   LIMIT STATE OF SERVICEABILITY
                                                                                                                     Design Guide Series 11 to satisfy serviceability requirements and
                          Serviceability loads shall be taken as the unfactored loads with all                       criteria for human comfort.
                          serviceability load combinations specified in the relevant codes used.
                                                                                                                6.   In order to ensure the durability of the structure under conditions
                          1.   Deflections of a building or part under serviceability loads                          relevant both to its intended use and to its intended life, the
                               should not impair the strength or efficiency of the structure or its                  following factors should be taken into account in design:
                               components, nor cause damage to the finishing.
                                                                                                                     •   Environment around the structure and the degree of
                          2.   Deflection limits shall not exceed the suggested values given in                          exposure.
                               Table 2. as per BS 5950.
                                                                                                                     •   Shape of the members and structural detailing.

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