Interim Report on Testing of Tension-only Steel Anchor Rods Embedded in Reinforced Concrete Slabs

摘要

When designing multi-story light-frame structures (i.e. woodrnor metal stud structures) over concrete podiums, lateral loadsrnfrom the structure above the podium will produce largerntensile forces in the overturning restraints. Tensile demandsrnin excess of 100 kips are not unusual. Currently, capacities ofrntension anchors embedded in concrete, when derived fromrnthe American Concrete Institute (ACI) 318-11 Appendix D,rncan be much lower than historic values.rnTests performed as part of an expanding research effort havernfocused on anchorage at both slab edges and center “field”rnlocations. Experimental data shows that the capacity ofrnembedded concrete anchorage can be significantly increasedrnthrough the addition of basic anchorage reinforcement, asrnallowed by ACI 318 Appendix D. This project investigatedrnthe conditions associated with shallow anchoragernreinforcement and its effect on behavior and capacity ofrnembedded anchors subjected to direct tension.rnThis interim report is aimed at providing useful findings torndesign professionals and building code officials forrnfrequently specified anchorage details. Importantrnrecommendations are also made related to constructionrnquality control and overall constructability. The goal of thernfinal test report is to enhance the findings with useful designrnrecommendations and data to support a successful proposal tornchange code provisions.rnThis small, ambitious testing project was initiated by severalrnpracticing engineers in Northern California. The bulk of thernreport findings were made possible by significant technicalrnand financial contributions from industry.