Steel Anchor Research Articles

Ductile Multiple‐Anchor Steel‐to‐Concrete Connections

Multiple‐anchor connections are commonly used in attaching steel members to concrete. A typical connection includes a steel attachment, the anchors that actually do the connecting, and an embedment of the anchors into the concrete. The behavior and design of these connections is not well‐defined by existing design standards. Multiple‐anchor connections can be divided into two categories, connections for which strength is controlled by the strength of the anchor‐steel, and connections for which strength is controlled by the strength of the embedment. Based on experimental research, the behavior and design of connections for which strength is controlled by the strength of the anchor steel is addressed. A behavioral model for determining the distribution of loads to the individual anchors in a connection is presented. The model is based on limit design theory. Experimental results are reported for 28 tests of multiple‐anchor connections loaded monotonically by various combinations of moment and shear. Test specimens included steel attachments with rigid and flexible base plates connected to concrete with threaded cast‐in‐place or retrofit (undercut and adhesive) anchors.

PCC Pavement Patching Materials and Procedures

Laboratory and field studies are conducted to evaluate three rapid‐setting PCC pavement patch materials and several construction techniques. Laboratory mix design studies reveal that PCC with and without steel fibers can be produced with early strengths adequate for one‐day patch construction. Four‐hour compressive strengths for these materials are lower than proprietary patch material, but after 5–6 hours their strengths are higher. Anchor optimization studies indicate that ultimate loads resisted by simulated patches are linearly proportional to the amount of anchor steel and that smaller anchor sizes perform best. During a field study the effects of pavement location and condition, construction temperature, anchors and sawing to outline patch areas are evaluated. Patches constructed of fibrous PCC perform best. The inclusion of anchors does not improve patch performance. Patches constructed during warm weather perform better than those constructed during cool weather. Patch performance is influenced by overall pavement condition with better patch performance on pavements with better condition. Sawing to outline patch area improves patch performance and aids patch construction.

有限要素法による地すべりの安定解析と対策工の設計

The limit equilibrium method has been used for the stability calculation of landslide submerged by reservoir water. However, it is difficult to evaluate the relationship between sliding distance and porewater pressure. The slope stability calculatioh by F. E. M. combined with joint element is studied to clarify the strain and stress condition along the slip surface, and also to analize the stress of steel pile and anchor works constructed in landslide area. In this paper, the claculation procedure by F. E. M. is discussed.

Fabric faced retaining wall with multiple anchors

Five years have passed since the construction of a 5 m high experimental fabric faced retaining wall incorporating reinforced columns and steel rod anchors. A part of the fabric was successfully replaced by a new one for experimental purposes. The retaining wall was dismantled in 1985. The fabrics were laid double, and the tensile strengths of the outer surface fabrics dropped by approximately 50%, and the inner by about 40%. The steel anchor rods were bent by the settlement of the backfill, but no malfunction of the anchors was observed. A new fabric retaining wall, of the same type, was constructed with a view to obtaining a more economical design. Precast concrete anchors were replaced with cast-in-place concrete blocks. Thus the basic principles of designing the fabric faced multiple anchored retaining wall were established.

The Cathedral Square substation anchored excavation, Vancouver, British Columbia

The paper describes the design of and construction experiences at a 20 m deep vertical excavation that was required in the heavily built-up downtown Vancouver area. The subsurface conditions may be generalized as an upper 3 m of sand and gravel followed by a sandstone sequence from fine to coarse with increasing depth. Depending on grain size and cementation, the compressive strength of sandstone varied from 6 to 30 MPa.The excavation support system consisted of soldier piles and posttensioned anchors in the overburden and posttensioned anchors and shotcrete in the rock face. Drainage control was provided by a system of deep, vertical perimeter drains connected to a number of near-horizontal drains in the rock face.The paper describes design considerations for the excavation, including an estimate of seismic-induced deformations. The construction aspects described include the use of a rapid cure method to predict grout strength, the use of couplers in anchor bars, and anchor load tests. During construction, a number of failures, attributed to stress corrosion, occurred in high tensile strength steel anchors. The details of the investigation and testing program used to provide an estimate of remaining anchor life are described. Finally, the paper summarizes results from the field instrumentation. Key words: anchors, construction, corrosion, deformation, drainage, excavation, failure, grout, instrumentation, stress.

Headed Steel Anchor under Combined Loading

The increasing use of headed steel anchor studs under combined shear and tension loading has resulted in a need for more information on their behavior and strength. Some typical situations where this type of loading is encountered in design are shown schematically in Fig. 1. Anchor studs can provide an efficient method of joining steel and concrete members and can permit greater flexibility in the design of composite steel-concrete systems. The existing criteria for designing headed steel anchor studs with partial embedment in concrete is based on limited test data and various models representing connector behavior. Several empirical relationships have been suggested in the literature. However, a number of factors can affect the ultimate strength of a headed steel anchor stud. They include the embedment length, the development of full or partial concrete shear cones which depends on anchor spacing and boundary conditions, concrete shear strength, shear friction, and the attachment plate thickness.

Stress Distribution in Rock Anchors

A finite element method is employed to analyze the stress distribution along a steel anchor bolt grouted into rock. Penetration of the yielded zone into the grout wall and redistribution of stresses with increasing load are illustrated. The effect of varying modular ratio in a two-material system subjected to tensile loads is also illustrated.

A non-linear analysis of the rotational stiffness of a nuclear steam generator foundation

A non-linear analysis of the moment-rotation relationships of a circular foundation for equipment of a nuclear steam supply system is presented. Equations are derived and numerical results given for 1) normal mild steel anchor bolts and circular base plate arrangement and 2) post-tensioned high-strength steel anchor bolts and circular base plate arrangement. An axisymmetric finite element computer program was applied for finding the stiffness of concrete in compression. The inelastic behavior of steel bolts is accounted for by an iterative procedure.

Underground corrosion on rural distribution lines

ANCHOR-ROD corrosion on multigrounded distribution lines has been found to occur as a result of galvanic action between copper-covered ground electrodes and galvanized steel anchor rods connected to the system neutral through uninsulated guys. This galvanic corrosion, while not observed in a majority of soils, has caused premature failures or excessively rapid deterioration of anchor rods in certain low-resistivity soils in North and South Dakota and in some other states west of the Mississippi River. Direct currents associated with the most usual corrosion reaction are shown in Fig. 1.

ELECTRIC CAST STEEL ANCHOR CHAIN.*

Journal of the American Society for Naval EngineersVolume 30, Issue 4 p. 850-852 ELECTRIC CAST STEEL ANCHOR CHAIN.* H. Jasper Cox., H. Jasper Cox.Search for more papers by this author H. Jasper Cox., H. Jasper Cox.Search for more papers by this author First published: November 1918 https://doi.org/10.1111/j.1559-3584.1918.tb01109.x * Paper read before the American Society for Testing Materials. AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Volume30, Issue4November 1918Pages 850-852 RelatedInformation

Foundations for transmission line towers and tower erection: II — Transmission tower steel anchors set in earth

As tower anchors have been somewhat overlooked causing in some instances much loss, these notes are written to call attention to the importance of properly designing them so that the maximum strength of tower may be obtained with the most economical outlay. The notes show: 1. A method of figuring the loads to be resisted by the anchors. 2. The importance of resisting the horizontal as well as the vertical loads. 3. The effect of the shape of the anchor on strength of tower. 4. Various types commonly used. 5. The economy of the use of an all-steel anchor.