Construction joints should be planned in advance and preferably y should be located at points of minimum shear and y should be nearly perpendicular to principal lines of stress and construction joints are generally eir vertical or horizontal.

The partial safety factor (?_m) for materials has a value depends upon importance of limit states being considered, materials when tested and when incorporated in construction during service life of structure.

The limit state of cracking is particularly important in case of partially prestressed members according to Abeles, who has contributed much information about members with limited prestress.

The statistical data required to define characteristic loads for different types of occupancy is not readily available, since loading statistics are invariably difficult to compile as y need a systematic observations and recording of data on loading and nominal imposed loads provided in various national codes, such as IS: 875-1987, BS: 6399 may be treated as characteristic loads.

The ultimate load design have been extended to design of continuous beams and frames where it is referred to as limit state design and this involves a redistribution of moments due to development of plastic hinges and an eventual collapse when last critical hinge formed.

Serviceability limit state corresponds to excessive deflection and cracking and it is customary in most codes to safeguard against excessive deflection under serviceability limit state, eir indirectly by prescribing minimum span/depth ratio for member or directly specifying a maximum permissible deflection expressed as a fraction of span.

In case of member subjected to axial tension, concrete section and minimum prestress are mainly controlled by Permissible stress at service loads and in some cases (walls of tanks) by practical considerations.

In case of flanged member on basis of collapse width and depth of compression flange is, while thickness of web is based on ultimate shear or a practical consideration of having curved cables with minimum cover requirements.

The bearing at support, anchorages or under concentrated imposed load, bond and various types of failure are also considered as bearing failure at supports, basically limit state design is a method of designing structures based on a statistical concept of safety and associated statistical probability of failure.

In absence of statistical data, characteristic strengths of concrete and steel may be taken as works cube strength and specified proof or yield strength respectively as provided for in codes.