Yes, by using a higher concrete grade, you can normally influence the load carrying capacity. However, it depends on the type of failure as well. If load carrying capacity is restricted due to a failure in the concrete then you can increase the concrete resistance by improving the quality of the concrete. However, if it is a steel failure, increased resistance will not be possible.
Hot-rolled profiles are hot-rolled from a single billet, and are free of internal stresses. Using this process material can be thickened at the highly loaded area of the profile such as channel lips. Due to the triangular shape of the channel lips, it is possible to apply high torques and thus high bolt tension forces. The high ductility and stress-free nature of the material makes this type of channel ideally suited to prevent fatigue in restraining rapidly oscillating loads, longitudinal loading, or dynamic load situations. Typical examples might be in resisting wind loads, seismic loading, blast loads, machinery anchoring, or guide rail conditions (elevators, or cranes). By contrast cold-formed channels typically have high stress at the corners and lip areas of the profile. This feature combined with work hardening during the forming process means that cold-formed channels have lower ductility, and a tendency towards sudden brittle failure in fatigue conditions. Consequently, cold-formed channels are recommended only for static loads and are not typically a good choice for supporting dynamic or fluctuating loads.
When the load is in the direction of a slot and only the top of the T-bolt is restrained by a serrated washer the shaft of the T-bolt is not directly supported by the bracket, and is subjected to additional bending stresses. Therefore in the JORDAHL® Expert design software; there is the option to consider slotted holes in the bracket and the additional bending of the bolt. The degree of restraint depends on the stiffness of the washer used. For a typical bracket connection recommended restraint values are between 1.6 and 1.8. If the slots in the brackets are to be later filled with grout, the bending does not have to be considered in the calculation.
On the T-bolt shank there is a safety notch which provides an easy visual check to confirm that the T-bolt has been fully rotated into the channel. Toothed and double toothed T-bolts have two parallel notches. After installation the safety notches on the T-bolts must be perpendicular to the longitudinal axis of the anchor channel.