Rolf Eligehausen

University of Stuttgart · Institute of Construction Materials

Structural behavior of reinforced concrete elements strongly depends on the interaction between the reinforcing bars and the surrounding concrete, which is generally referred as “bond in concrete”. In service conditions, the reinforcement-to-concrete bond governs deformability through the tension stiffening of concrete surrounding the bar as well t...

Structural behavior of reinforced concrete elements strongly depends on the interaction between the reinforcing bars and the surrounding concrete, which is generally referred as “bond in concrete”. In service conditions, the reinforcement-to-concrete bond governs deformability through the tension stiffening of concrete surrounding the bar as well t...

Structural behavior of reinforced concrete elements strongly depends on the interaction between the reinforcing bars and the surrounding concrete, which is generally referred as “bond in concrete”. In service conditions, the reinforcement-to-concrete bond governs deformability through the tension stiffening of concrete surrounding the bar as well t...

Increasing worldwide urbanization pushes city centers to grow in height. The skylines of cosmopolitan cities are increasingly dominated by tall buildings clad with curtain wall façade panels. In many cases, these panels are attached to the structure by anchor channels. One of the challenges of this is that the concrete decks are becoming thinner an...

In recent years, the use of post-installed anchors to connect the haunch elements with the structural members has been investigated proficiently. It represents a promising alternative for strengthening of joints of existing reinforce concrete (RC) structures (moment resisting frames) with low invasion. The efficacy of the fully-fastened-haunch-retr...

The presence of in-situ cast slabs and transverse beams in reinforced-concrete (RC) beamcolumn joints is usually neglected in RC design practice concerning frames subjected to seismic actions for at least two reasons: (i) the need of simplification in the design process and (ii) the limited experimental studies which are mainly focused on two-dimen...

The recent revision of a guideline in the United States allows for the first time ever the qualification of post-installed reinforcing bars for end anchorages and overlap splices. The design of end anchorages and overlap splices with post-installed reinforcing bars can now be carried out using provisions for cast-in-place reinforcing bars. Alternat...

Dieses Kapitel beschreibt die Grundlagen der Bemessung von Verankerungen in Beton nach EN 1992‐4 und die Ableitung der Lasteinwirkungen bei statischer und quasi‐statischer Belastung. Es erklärt den Nachweis für Kopfbolzen und mechanische beziehungsweise chemische Dübel im Grenzzustand der Tragfähigkeit und die Plastizitätstheorie. Während in der CE...

EN 1992-4 [1] regulates the design of fastenings in concrete. It contains provisions for fastenings at an edge with supplementary reinforcement to take up shear forces perpendicular to the edge. The model given in [1] is very conservative. Therefore tests were performed at the University of Stuttgart to investigate the behavior of fastenings with u...

de Die neue EN 1992‐4 wurde auf Basis der bewährten Vornormenreihe CEN/TS 1992‐4 zum Eurocode weiterentwickelt und in einem Dokument zusammengefasst. Sie enthält Bemessungsverfahren für Kopfbolzen, mechanische und chemische Befestigungsmittel sowie Ankerschienen in tragenden Beton‐ und Stahlbetonkonstruktionen. Voraussetzung für die Bemessung nach...

Anchors are widely used for structural and nonstructural connections to concrete. If used in earthquake prone areas, concrete anchors have to resist seismic actions such as cyclically pulsating loads and cyclically opening and closing cracks which potentially intersect the anchor location. In reality, cyclic load and cyclic crack phenomena act on a...

Anchors are widely used for structural and nonstructural connections to concrete. If used in earthquake prone areas, concrete anchors have to resist seismic actions such as cyclically pulsating loads and cyclically opening and closing cracks which potentially intersect the anchor location. In reality, cyclic load and cyclic crack phenomena act on a...

Anchorages with post-installed reinforcing bars can be designed either as end anchorage equivalent to cast-in reinforcing bars or as adhesive anchors. Both design methods are established and codified. The two design methods are different in their range of application and fundamental approach. It is therefore not surprising that the two design metho...

Anchorages in concrete may be subjected to tension forces, shear forces or combined tension and shear forces (interaction). The performance of anchorages can be enhanced by providing supplementary reinforcement against tension or shear forces in the form of stirrups enclosing surface or edge reinforcement, respectively. Previously, the authors carr...

Cast-in fastenings for use in concrete are widely used in Australia. While design guidelines for headed fasteners are currently in place in Europe and the US, guidance on the design of hold-down bolts and hooked bolts (J- and L- bolts) is currently only available in the US. These types of fastenings to concrete are frequently used in safety-critica...

Ductility plays an important role in structural and seismic engineering. Its beneficial effect on load distribution and performance during earthquakes is assumed to be true also for anchors connecting concrete and steel elements. However, a conclusive definition of anchor ductility is not given yet in the relevant qualification guidelines and desig...

The models included in the current standards and guidelines (EN1992-4, ACI 318, fib Bulletin 58) to evaluate the failure loads for anchorages with supplementary reinforcement in the form of hanger reinforcement and stirrups subjected to either tension or shear forces are conservative compared with the results of corresponding experiments. In this w...

The behavior of anchorages with multiple headed studs is significantly influenced by the presence of supplementary reinforcement. Under the action of tension forces or the shear forces perpendicular and towards the edge, the behavior of anchorages with supplementary reinforcement can be best described using a strut-and-tie model. The forces applied...

A critical performance aspect of FRP retrofitted concrete elements is the bonding of the FRP sheet to the concrete surface. In general, the performance is limited by the debonding of the loaded FRP sheets from the concrete surface. One method to delay debonding and enhance the capacity is the use of FRP anchors which interlock the FRP sheet to the...

Im Stahlbetonbau müssen die einzelnen Bauteile miteinander verbunden werden, z.B. Balken mit Stütze oder Stütze mit Fundament. [...]

An extensive numerical study was carried out to evaluate the influence of concrete member thickness and orthogonal surface reinforcement on the tensile capacity and performance of anchor bolts in uncracked concrete members. Anchor bolts at various embedment depths (hef = 50 to 300 mm [1.97 to 11.81 in.]) in unreinforced and reinforced concrete memb...

This study evaluated the influence of concrete member thickness and size of anchor head on the tensile capacity and performance of anchor bolts in concrete. Anchor bolts at various embedment depths (hef = 50 to 500 mm [1.97 to 19.69 in.]) in concrete members of various thicknesses (H = 1.5 to 5.0hef) were simulated. Three different sizes of anchor...

The behavior of anchorages with multiple headed studs is significantly influenced by the presence of supplementary reinforcement. The supplementary reinforcement to resist tension forces on the anchorage consists of surface reinforcement and the stirrups, usually enclosing the surface reinforcement. For the anchorages placed close to the edge and l...

The models included in the current standards and guidelines 1,2,3 to evaluate the failure loads for anchorages with supplementary reinforcement subjected to either tension or shear forces are very conservative. The existing models do not explicitly consider all three major components that provide resistance to applied forces for anchorages with sup...

The load transfer within joints of reinforced concrete elements can strongly influence the behavior of the structure. Also cracks play an important role which develop due to bending induced tensile stresses in concrete and meander along the starter bars anchored in joints. The performance of joints becomes even more relevant under seismic loading c...

The paper presents a new model for predicting the resistance of anchorages with supplementary reinforcement loaded in shear toward and perpendicular to the edge in case of reinforcement failure. The model is based on the evaluation of the results of a comprehensive test program performed on anchorages with multiple anchor rows and supplementary rei...

The American Concrete Institute (ACI) standards for qualification of post-installed concrete anchors (ACI 355.2 and ACI 355.4) include a nonseismic crack movement test characterized by a large number of small-amplitude crack cycles. This paper investigates anchor response to a new stepwise-increasing cyclic crack protocol with a number of crack cyc...

Anchors used in seismic applications have to resist cyclically pulsating loads and cyclically opening and closing cracks which potentially intersect the anchor location. In reality, cyclic load and cyclic crack phenomena act on anchors simultaneously; however, seismic tests in laboratories are carried out with either one of the two parameters kept...

Cyclic loads are a characteristic feature of actions acting on structures and anchorages during earthquakes. For this reason, seismic qualification of post-installed concrete anchors according to the internationally recognized American Concrete Institute (ACI) standards ACI 355.2 and 355.4 are based on cyclic load tests. The protocols for these cyc...

Nonstructural components and systems are typically connected to concrete structures by means of post-installed anchors. Despite their widespread use, very little is known about the behavior of post-installed anchors when used in a system and loaded during an earthquake. The study presented in this paper was conducted to investigate the seismic perf...

The presence of supplementary reinforcement, in the form of edge reinforcement and stirrups, has a significant influence on the load-bearing capacity of anchorage groups with multiple anchor rows loaded in shear perpendicular to the edge. The current models available in the codes and standards are conservative for low to medium amounts of supplemen...

Additional columns are often used as a retrofitting solution for reinforced concrete structures, particularly in seismic regions. These columns require postinstalled starter bars that inhibit the detailing of the anchorage with hooks. Often, the anchorage length of straight starter bars cannot be accommodated in foundations, which are generally sho...

Due to their general robust behaviour and high reliability, embedded parts (EPs) as a group of headed studs welded to an anchor plate cast in concrete are heavily used in nuclear power plants. Frequently, the EPs consist of headed studs arranged in more than one anchor row. Typically, the concrete slabs in which the EPs are cast have significant am...

Two different design methods for anchorages with post-installed reinforcing bars are available: Anchorages can be designed either as end anchorage equivalent to cast-in reinforcing bars or as bonded anchors. The two design methods are very different in their fundamental approach and range of application. This contribution presents both design metho...

In nuclear power plants (NPPs), post-installed anchors are widely used for structural and non-structural connections to concrete. In many countries, anchor products employed for safety relevant applications have to be approved by the authorities. For the high safety standards in force for NPPs, special requirements have to be met to allow for extre...

Synopsis: Pullout tests with headed studs placed near a free edge have been carried out. In most of the tests blow-out failure occurred. On the basis of this and other available test results an empirical equation for calculating the failure load was derived. The equation takes into account the influence of the edge distance, the concrete strength a...

Für den Entwurf von nachträglich installierten Anschlussbewehrungen stehen zwei Bemessungskonzepte zur Verfügung: Eingemörtelte Bewehrungsstäbe können entweder wie einbetonierte Bewehrungsstäbe oder als Verbunddübel betrachtet und bemessen werden. Beide Bemessungskonzepte haben ihre Anwendungsbedingungen und -bereiche, die sich überschneiden. Diese...

Für den Entwurf von nachträglich installierten Anschlussbewehrungen stehen zwei Bemessungskonzepte zur Verfügung: Eingemörtelte Bewehrungsstäbe können entweder wie einbetonierte Bewehrungsstäbe oder als Verbunddübel betrachtet und bemessen werden. Beide Bemessungskonzepte haben ihre Anwendungsbedingungen und -bereiche, die sich überschneiden. Diese...

Insufficient anchorage of nonstructural components is a substantial cause of earthquake damage. To investigate this issue, shake table tests were conducted on model nonstructural components suspended and supported via anchors cast in cyclically cracked concrete. Concrete slabs supporting the anchored model component were subjected to seismic floor...

Earlier studies have shown that post-installed reinforcing bars are capable of developing bond behavior equivalent to cast-inplace reinforcing bars. Therefore, connections with post-installed starter bars using qualified adhesives can be designed according to conventional anchorage design provisions. However, this approach often results in developm...

Post-installed anchors are often used to fix nonstructural components and systems (NCS) to concrete. For applications in earthquake prone areas, the anchors have to be qualified for the extreme demands arising from seismic actions. As the structure responds to the ground motion, the anchor loads develop according to the inertial response of the NCS...

Under the action of seismic forces, joints of RC frame structures are subjected to large shear stresses in the core. The seismic performance of RC frame structures is often governed by the behavior of its beam-column connections. This is especially true for the case of non-seismically designed frame structures that were constructed following old an...

Seismic behaviour of anchorages in concrete construction has relatively recently being explored as an important research topic. The safety of various structural and non-structural components connected using the headed fasteners or post-installed anchorages depend on the seismic performance of the anchorage used for the connection. The seismic perfo...

In general, column starter bars have to be provided with hooks when designing the reinforcement of column-to-foundation connections according to structural reinforced concrete codes since the foundation member height cannot accommodate the required straight anchorage length. Hooked bars, in turn, often cause reinforcement conflicts and impede the p...

Haunch retrofit solution (HRS) has been relatively recently investigated as a viable alternative for retrofitting of beam-column joints of reinforced concrete (RC) frame structures. For connecting the haunch elements to the frame members, partially prestressed rods were used. However, this solution makes it difficult for implementation in practice...

Dieses Kapitel beschreibt Ankerschienen, die aus C-förmigen Stahlprofilen bestehen, die zum Schutz gegen das Eindringen von Frischbeton mit Polystyrol- oder PE- Schäumen gefüllt sind. Diese Ankerschienen nutzten zur Verankerung im Beton im wesentlichen Flachstähle, die auf der Baustelle durch Aussparungen im Profilrücken oder in angewalzten Stegen...

Bonded anchors consist of steel elements (e.g. threaded rods) which are bonded into a drilled hole by a prequalified adhesive mortar. They are designed according to ACI 318 Appendix D “Anchoring to Concrete”. Reinforcing bars post-installed in drilled holes by a suitable mortar behave like cast-in reinforcing bars. They are designed according to AC...

Under the action of seismic forces, joints of RC frame structures are subjected to large shear stresses in the core. The seismic performance of RC frame structures is often governed by the behavior of its beam-column connections. This is especially true for the case of non-seismically designed frame structures that were constructed following old an...

One of the most severe deficiencies in RC frame structures making it vulnerable against earthquakes is the inadequate shear resistance of beam-column joints. To improve the seismic performance of the structure, improving the performance of its joints is essential. Fully fastened haunch retrofit solution (FFHRS) has been proven to be an efficient an...

As part of the preparation for the fib Model Code for Concrete Structures 2010, task group 4.5 Bond Models undertook a major review of rules for bond and anchorage of reinforcement in the CEB-FIP Model Code 1990. This bulletin presents the outcome of that review, describes the rationale for the revisions and presents the evidence on which the revis...

Fully fastened haunch retrofit solution (FFHRS) has been proven to be an efficient and effective retrofitting technique to safeguard the beam-column joints by modifying the hierarchy of strength converting the undesirable joint shear failure mode to a desirable beam flexure failure mode. Experiments at joint sub-assemblies under cyclic loads as wel...

Post-installed anchors are often used to fix non-structural components to the primary concrete structure. To ensure safe connections, anchor products have to be qualified according to relevant qualification guidelines. Their test programs include so-called crack movement tests for which the anchor is installed in a concrete specimen with a predefin...

Einleitung Anwendungsbereich Grundlagen der Bemessung Ableitung der Lasteinwirkungen Nachweis von Dübeln (mechanische Systeme) im Grenzzustand der Tragfähigkeit auf Basis der Elastizitätstheorie Nachweis von Dübeln (chemische Systeme) im Grenzzustand der Tragfähigkeit auf Basis der Elastizitätstheorie Nachweis von Kopfbolzen im Grenzzustand der Tra...

General Verifications Partial factors

General Tension forces in the supplementary reinforcement Tension load Shear loads Combined tension and shear loads

General Basis of design Resistances under tension and shear load

General Tension forces in the supplementary reinforcement Tension load Shear load Combined tension and shear load

General Additions and alterations to EN 1998-1:2004 (Eurocode 8) Verification of seismic loading

General Tension load Shear load Combined tension and shear

General Conditions of application Distribution of external forces to the fasteners of a group Design of fastenings

General Tension load Shear load Combined tension and shear load

General Tension loads Shear loads Tension forces in a supplementary reinforcement

General Fasteners in dry, internal conditions Fasteners in external atmospheric or in permanently damp internal exposure and high corrosion exposure

Inelasticity in RC frame structures, due to seismic loads, is generally considered to be concentrated in the form of hinges in beams, columns and joints. In this paper, the parameters for rectangular RC beams, columns and non-seismically detailed beam-column joints are suggested keeping the simplicity of the original pivot hysteresis model. With th...

Plattenanschlüsse sind in der Praxis gängige Konstruktionselemente zur Vermeidung von Schimmelpilz und zur Gewährleistung erhöhter bauphysikalischer Anforderungen. Derartige Elemente bestehen in der Regel aus Stahlzug- und Stahlquerkraftstäben sowie aus Beton- bzw. Stahldrucklagern. Beim Halfen-Iso-ElemenT HIT-HP/HIT-SP wurde das statische System w...

Inelasticity in reinforced concrete (RC) frame structures due to seismic loads is generally considered to be concentrated in the form of hinges in beams, columns, and joints. In this paper, the parameters for rectangular RC beams, columns, and nonseismically detailed beam-column joints are suggested, keeping the simplicity of the original pivot hys...

The paper presents experimental and numerical work carried out on a full-scale four storey reinforced concrete (RC) structure for seismic assessment by pushover method. For practicality, a portion of an existing structure having certain eccentricities was replicated for the experimental setup. The structure was detailed as per non-seismic reinforce...

In reinforced concrete (RC) framed structures, especially non-seismically designed, beam-column joints are the key structural elements, which dictate the behavior of structures subjected to earthquake loading. In performance analysis of RC frame structures, generally the joint core is considered as rigid and all the plastic rotations are assumed to...

Robust earthquake resistant connections are important to avoid substantial damage to nonstructural components and systems (NCS) and to limit costs associated with failure or loss of functionality of the NCS. Suspended NCSs are particularly noted for rendering excessive downtime in past earthquakes. In order to deepen the understanding of the seismi...

The post-installation of reinforcing bars at low ambient temperatures may increase the creep rate and decrease the strength. The relationship between a low curing temperature and the short-term and long-term capacity has not been investigated in detail yet. In a first step tests employing an epoxy based mortar were carried out to investigate the cr...

As reinforced concrete structures respond to seismic excitation, the reinforcing bars are cyclically loaded. Simultaneously, cracks along reinforcing bar anchorages in joints open and close due to the cyclic response of the structure. The bond characteristic between reinforcing bars and concrete can have a significant influence on the seismic load...

Recent studies showed that post-installed reinforcing bars develop a bond stress-slip behavior equivalent to cast-in-place reinforcing bars, provided a suitable adhesive is used. However, the post-installed starter bars have to be designed according to the conventional reinforced concrete design concept. The resulting straight development length ca...

To determine the bond behavior of ribbed bars under repeated loads, 308 pullout specimens were tested. The specimens failed by pulling out of the bars. In the tests the following parameters were varied: maximum load and load amplitude, bar diameter, concrete quality, and bond I. ength. Furthermore, as a comparison, tests under sus-tained load were...

Synopsis: Computer analyses of the pull-out tests of anchors embedded in concrete were performed for the Round Robin Analysis of the RILEM Committee on Fracture Mechanics of Concrete. The test specimens are con-crete plates with steel anchors in the plane stress state. The geometry of the specimen is varied in order to study the size effect and the...

Synopsis: Reinforced concrete structures will generally be cracked under service load due to tensile stresses caused by loads or by the restraint of imposed deformations. Therefore, in general, the design of anchors should be based on the assumption that the concrete is cracked. Under tension loading anchor behavior is significantly influenced by c...

Synopsis: An experimental program was carried out to investigate the behaviour of metallic fasteners (undercut, torque controlled expansion and chemical anchors) embedded in cracked concrete and subjected to shear displacements. The results show that the behaviour of all three types of anchors under shear displacements is similar. Fasteners situate...

Synopsis: The behavior of metallic expansion anchors under monoto-nic loading is described on the basis of 3 large number of avail-able test results . Expansion anchors loaded in tension viII often fail in a rather brittle manner by pulling out a concrete cone. The corresponding failure load Fu is approxUa3tely proportional to f ct . Id 1 • 5 (f ct...

Seit 1975 wurden Verbundankersysteme verschiedener Firmen bauaufsichtlich zugelassen, wobei die Systeme hinsichtlich der Zusammensetzung des Mörtels praktisch identisch sind. Diese Zulassungsbescheide regelten die Verwendung von Einzelankern sowie Ankerpaaren mit Ankern in der aus Lastspannungen erzeugten Druckzone von Beton- und Stahlbetonbauteile...

Die moderne Befestigungstechnik wird in steigendem Maße gezielt bei der Planung und Ausführung von Ingenieurbauwerken eingesetzt. Sie erlaubt die wirtschaftliche Anwendung einfach und zeitsparend montierbarer Dübel, die in nachträglich erstellten Bohrlöchern in Beton- oder Stahlbetonbauteilen verankert werden. In diesem Beitrag werden die unterschi...

Die moderne Befestigungstechnik wird in steigendem Maße gezielt bei der Planung und Ausführung von Ingenieurbauwerken eingesetzt. Sie erlaubt die wirtschaftliche Anwendung einfach und zeitsparend montierbarer Dübel, die in nachträglich erstellten Bohrlöchern in Beton- oder Stahlbetonbauteilen verankert werden. In diesem Beitrag werden die unterschi...

Eine wesentliche Voraussetzung für die Rationalisierung der Bewehrungstechnik ist, wie zum wiederholten Male dargelegt, die Standardisierung der Bewehrungsformen einschließlich Vermaßung und Bezeichnung und die Vereinfachung und Standardisierung der Bewehrungszeichnungen.. Entsprechende Vorschläge aus dem Ausland liegen vor, die - gegebenenfalls na...