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Introduction
Published in Malcolm D. Bolton, Akio Kitamura, Osamu Kusakabe, Masaaki Terashi, New Horizons in Piling, 2021
Malcolm D. Bolton, Akio Kitamura, Osamu Kusakabe, Masaaki Terashi
However, properly embedded structures can be considered to be resilient against even a severe tsunami. The embedment effects increase the vertical bearing capacity largely due to overburden pressure, and increase the pullout resistance (negative vertical bearing capacity) due to frictional resistance along the periphery of the embedded parts of the structure. The embedment effects also increase the horizontal resistance mainly due to the mobilization of passive earth pressure on the side walls of the embedded elements of the structure. Similarly, the moment resistance increases benefitted by the mobilization of passive earth pressure as well as frictional resistance at the side walls and at the base of the structure.
Introduction
Published in Charles Aubeny, Geomechanics of Marine Anchors, 2017
As shown in Figure 1.31, an overloaded anchor can either experience a loss of embedment or continue to dive downward, according to the system of forces acting on the anchor, specifically the angle of the mooring line at the mudline, the fluke angle, and the fluke–shank angle. As discussed earlier in the discussion of VLAs, orienting the anchor shank normal to the fluke maximizes anchor load capacity, but it also promotes a brittle failure mode. The “near-normal” design concept for VLAs typically limits the fluke–shank angle to less than 75–80° to reduce the tendency for upward motion of the anchor. This practice is consistent with plasticity-based analysis by Aubeny and Chi (2014) indicating a brittle failure mode becomes more likely for fluke–shank angles greater than 80°. Furthermore, influencing the kinematic behavior of the anchor is the mooring line angle at the mudline and the anchor fluke angle. For mooring line angles greater than 45°, a brittle failure mode is likely to occur irrespective of the anchor design. As taut mooring lines are frequently less than this angle, it is therefore not unrealistic to expect that a properly designed VLA can dive when overloaded. As shown in Figure 1.31, the fluke angle also influences whether an anchor will rise or dive. Theoretical analyses and observed behavior of drag embedment (discussed in Chapter 9) show that the anchor fluke angle decreases with increasing drag distance and anchor embedment depth. Thus, increased embedment gives the benefit of increased load capacity, but also increases the potential for a brittle failure mechanism. Similar to any plate anchor, helical anchors can experience brittle failure under vertical loading, but retorqueing to restore lost embedment is conceptually possible.
Numerical analysis of concrete-encased tubular base connections
Published in Amin Heidarpour, Xiao-Ling Zhao, Tubular Structures XVI, 2018
A. Albareda-Valls, J. Maristany Carreras, S.S. Zaribaf
The embedment provides extra rigidity and ductility to the base than usual base plates supported by anchor bolts. Despite the significant advantages of the embedded connection, this solution is less used due to the standard timings in construction works. This is the reason why also a new typology of semi-embedded sections has become also used in Japan (Wang et al., 2009), (Morino et al. 2003), (Kim et al. 2015), (Qiao et al. 2012).
Serviceability performance of buildings founded on rubber–soil mixtures for geotechnical seismic isolation
Published in Australian Journal of Structural Engineering, 2023
Hing-Ho Tsang, Duc-Phu Tran, Emad F. Gad
Various analytical models have been developed over the past few decades for estimating the settlement of a foundation sitting on clay or sand deposits (Bowles 1987; Mayne and Poulos 1999; Schmertmann, Hartman, and Brown 1978; Skempton and Bjerrum 1957). Skempton and Bjerrum (1957) conducted an analysis of the immediate settlement of cohesive materials based on the theory of elasticity. Schmertmann, Hartman, and Brown (1978) introduced a semi-empirical strain influence factor to estimate the foundation settlement of granular material. The proposed analytical formula also takes into account the depth of foundation embedment and creep in soil. Bowles (1987) developed another expression that consists of a shape factor and a depth factor for estimating the settlement of flexible foundations based on the theory of elasticity. More recently, to consider the rigidity and the depth of embedment of the foundation, as well as the variation of elastic modulus of soil against depth, Mayne and Poulos (1999) proposed an improved formula for estimating the elastic settlement at the centre of the foundation. A summary of the four analytical models for estimating foundation settlement is given in Table 4.
Concurrent modelling of carbonation and chloride-induced deterioration and uncertainty treatment in aging bridge fragility assessment
Published in Structure and Infrastructure Engineering, 2020
Mohamed Mortagi, Jayadipta Ghosh
Similar to bridge columns, the corrosion deterioration in the bearings may lead to a reduction of cross-sectional area of anchor bolts as well as keeper plate thickness (Ghosh & Padgett, 2010). Additionally, the bearing coefficient of friction may increase due to debris accumulation along the service life (Ghosh & Padgett, 2010; Mander et al., 1996; Silano & Brinckerhoff, 1993). Following the suggestions in Ghosh and Padgett (2010), the time-dependent ultimate lateral strength for high-type fixed bearings along the longitudinal Fu,long(t) and transverse direction Fu,trans(t) are computed as:where, αb and N are the number of bolts and axial load on the bearing respectively, wl and wt are the width of masonry plate in the longitudinal and transverse directions, fc is the concrete compressive strength, b1 is the distance between the anchor bolt and the masonry plate centre and h is the bearing height from the concrete pedestal to the sole plate-rocker interface. The time-dependent bond strength B(t) in Equation (20) can be computed as:where, db(t) is the anchor bolt diameter, ld is the embedment length of the anchor bolt and bu is the bond stress on the anchor bolt surface (assumed to be uniform over the embedment length).
Fatigue of glued-in rods in engineered hardwood products — part I: experimental results
Published in The Journal of Adhesion, 2019
S. Myslicki, O. Bletz-Mühldorfer, F. Diehl, C. Lavarec, T. Vallée, R. Scholz, F. Walther
For the threaded rods glued into Beech-LVL (shown in Figure 12(a)) with the parameter combination Beech-LVL-Wü 500-thr. rod, the slope of the regression line for wood/adhesive-interface failure is b = –6.4 for the embedment length of lad = 10 × d, and b = –5.1 for the reduced embedment length of 6 × d. The maximal Forces for lad = 6 × d are reduced to about 60%, compared to that reached by lad = 10 × d. The reduction of the embedment length of 40% leads to a reduction of maximum forces by roughly the same proportion. It must, however, be considered that the Basqiun approximation for lad = 6 × d is only based on two data points in the HCF-range, where the data points at Fmax = 30 kN are similar and the data point at Fmax = 40 kN for lad = 6 × d is close to the approximation of lad = 10 × d. It is assumed that the embedment length does not influence the fatigue behaviour of the rods when rod failure is involved. This will be validated in an additional test series presented later within this study. The fatigue strength is finally determined by rod failure, and amounts to Fmax = 20 kN. This results in the fact that the reduction of the embedment length does not influence the fatigue strength.