THE LOWER LIMITS OF THE LIMIT LOADS OF PERFECTLY PLASTIC STRUCTURES

A general method of obtaining the lower limits for limit loads is desc ribed, the essentials of which are as follows. The load acting on a st ructure is represented in the form of a functional series in powers of certain fundamental loads, for each of which, applied separately, the limit load coefficient (LLC) or a lower estimate for it is found. Usi ng those estimates, the corresponding statically admissible stress fie lds and the coefficients of the expansion in the functional series, th e lower limit is found for the LLC for the initial load distribution. Using the system of lower limits of the LLC for fundamental loads, a l ower limit of the LLC for any distribution, including an alternating-s ign distribution, can be found. This can be very useful when the load distribution on the structure changes with time, as in the case of exp osure to snow or wind.