Manholes, handholes, and vaults shall be designed to sustain all expected loads which may be imposed on the structure. The horizontal and/or vertical design loads shall consist of dead load, live load, equipment load, impact load due to water table or frost, and any other load expected to be imposed on and/or occur adjacent to the structure. The structure shall sustain the combination of vertical and lateral loading that produces the maximum shear and bending moments in the structure.

In roadway areas, the live load shall consist of the weight of the moving tractor-semitrailer truck illustrated in Fig. 31.1. The vehicle wheel load shall be considered applied to an area as indicated in Fig. 31.2. In case of multilane pavements, the structure shall sustain the combination of loadings which result in vertical and lateral structure loadings which produce the maximum shear and bending moments in the structure. Loads imposed by equipment used in road construction may exceed loads to which the completed road may be subjected.

In designing structures not subject to vehicular loading, the minimum live load shall be 300 lb/ft ². Live loads shall be increased by 30 percent for impact. When hydraulic, frost, or other uplift will be encountered, the structure shall be either of sufficient weight or so restrained as to withstand this force. The weight of equipment installed in the structure is not to be considered as part of the structure weight. Where pulling-iron facilities are furnished, they should be installed with a factor...