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This study documented three-dimensional spinal loading associated with asymmetric lifting while using either one or two hands to perform the task. Lift asymmetry was defined as a function of the load origin relative to the sagittal plane of the body. Lifts occurred at 0, 30, or 60 degrees off the sagittal plane on both sides of the body (lifting from the right and from the left relative to the sagittal plane). Ten subjects lifted a 13.7 kg box from one of these origins to a sagittally symmetric destination. Spinal loads were estimated through the use of a validated EMG-assisted model. Spine compression and lateral shear forces increased as the lift origin became more asymmetric. However, spinal compression and lateral shear increased by about twice the rate when lifting from origins to the left of the sagittal plane compared to lifting from origins to the right of the sagittal plane. Anterior-posterior spinal shear decreased as asymmetry increased with larger decreases occurring when lift origins occurred to the right of the sagittal plane. One-hand lifting changed the compression and shear profiles significantly. One-hand lifts using the hand on the same side of the body as the load resulted in compression forces that were approximately equal to those observed when lifting with two hands in a sagittally symmetric position. Anterior-posterior shear decreased and lateral shear increased under these conditions. These results reflect the trade-offs that must be considered among spinal forces during asymmetric lifting while using one or two hands. These findings have significant implications for task assessment interpretation and workplace design.

Recent results from full-scale static racking tests and small-scale lateral shear tests on plywood, oriented strand board (OSB), gypsum wallboard (GWB), and FiberBond wallboard (FB) attached to light gauge steel studs are presented and discussed in this paper. The objectives of the tests were to investigate the performance of sheathed light gauge steel framed shear walls and determine whether simple static lateral shear values for the panel connection can provide a useful correlation with full-scale test values. The full-scale tests were conducted in accordance with the basic test criteria defined in ASTM E 72-80. A procedure similar to that described in ASTM D 1761-88 was used for the small-scale tests. Panels used in the tests included 11.9 mm APA rated four-ply plywood sheathing, 11.1 mm APA rated OSB sheathing, 12.7 mm gypsum wallboard (ASTM C 36), and 12.7 mm FiberBond wallboard. Results obtained from tests showed that failure of the walls resulted from rotation (tilting) of the fasteners about the p...

This study demonstrates the utility of a modified postero-medial surgical approach to the knee in treating a series of patients with complex tibial plateau injuries with associated postero-medial and postero-lateral shear fractures. Posterior coronal shear fractures are underappreciated and their clinical relevance has recently been characterised. Less-invasive surgery and indirect reduction techniques are inadequate for treating these coronal plane fractures. Our approach includes an inverted 'L'-shaped incision situated within the posterior flexor knee crease, followed by the retraction or incision of the medial head of the gastrocnemius tendon, while protecting the neurovascular structures. This provides a more extensile exposure, as far as the postero-lateral corner, than previously described. Our case series included eight females and eight males. The average age was 53 years. The majority of these injuries were sustained through high-energy trauma. All patients' fractures were classified as Schatzker grade 4, or above, with a postero-medial split depression. Eight patients had associated postero-lateral corner fractures. Two were open, two had vascular compromise and one had neurological injury. The average time to surgery was 6.4 days (range 0-12), operative time 142 min (range 76-300) and length of stay 17 days (range 7-46). A total of 11 patients were treated using the postero-medial approach alone and in five the treatment was combined with an antero-lateral approach. Two patients suffered a reduced range of movement requiring manipulation and physiotherapy, and three patients had a 5-degree fixed flexion deformity. Two patients developed superficial wound infections treated with antibiotics alone. Anatomical reduction and fracture union was achieved in 15 patients. These are complex fractures to treat, and our modified posterior approach allows direct reduction and optimal positioning of plates to act as buttress devices. It can be extended across the midline to the postero-lateral corner and also allows excellent exposure of the popliteal vessels should concurrent vascular repair be required.

Two-stage open-channel flow is physically modeled using air as the working fluid in a straight, wide, smooth, closed duct of compound cross section. Time-averaged velocity and boundary shear-stress measurements are analyzed and presented in a form pertaining to the lateral shear-layer mechanism.

It is shown theoretically and by experiment that dual exposure recording of Gabor holograms of an amplitude scattering mask leads to twice the normal sensitivity for the same amount of shift in a lateral shear interferometer of axial wavefront aberrations of a controllable wavefront.

The instream flow incremental methodology (IFIM) needs to be improved to more reliably predict the effects of altering fish habitat. Two-dimensional (2-D) hydrodynamic modeling with moving boundaries by the finite element approach overcomes may limitations related to classical physical habitat simulation modeling (mostly 1-D). Some of its most important properties are: the spatial resolution of the model can be adapted to the scale of individual fish habitats and to the spatial variability of field data; the areas frequently uncovered because of flow regime are correctly taken into account through the drying–wetting capability; and the flow resistance variables are more accurate in 2-D because they can be specified as functions of the local substrate conditions or lateral shear stresses. This approach is illustrated by a study of the habitat of juvenile Atlantic salmon Salmo salar of the Moisie River (Quebec) where a water diversion has been planned. The results of simulations carried out at two ...

An analysis in the Fresnel approximation is given of the formation conditions of lateral-shear holographic interferograms in bands of infinite width characterizing the wave aberrations of a microscope optical system over the field in the case of coherent diffuse illumination of a ground-glass screen.

The governing equations of three-dimensional problems in transversely isotropic piezo-electric material are composed of four second order partial differential equations, in which the displacement components and electric potential functions are the essential unknowns. In this paper the so-called general solutions of these equations are obtained with the aid of a set of new potential functions which are used to express the components of displacements and the electric potential functions. As an application of the general solution the problem of a half-space piezoelectrics acted by a concentrated lateral shear force is solved.

In this paper, spruce-steel-spruce flitch joints connected by shot fired nails are subjected to short term loads. The failure modes and design resistance equations are compared with those detailed in Eurocode 5. The formation of a plastic hinge is observed in the nails at the steel-timber interface and Mode I (tensile opening) occurs longitudinally along the grain following the row of nails. The predictive equations of force in Eurocode 5 for dowel-type joints are modified with respect to yield moment and unequal fastener penetration depths to produce a significantly improved predictive equation for force.

A technique for the interpretation of interferograms with a spatial carrier, based on a phase-lock loop method has been recently developed. This method is applied to the analysis of lateral shearing interferograms. The great advantage of this procedure is that there is no need for any explicit phase unwrapping, since this is implicit within the phase-locked loop method.

Present a method for computing the embedded depth in rock of the laterally loaded rock-socketed piles. The method, based on the Hoek-Brown failure criterion, takes into account the mobilized lateral shear resistance along the bond of perimeter of the pile in rock. The proposed method is verified to be more reasonable by comparing its result with that of other existing methods.

A variable shear lateral shearing interferometer consisting of two holographically produced crossed diffraction gratings is used to test nonrotationally symmetric wavefronts having aberrations greater than 100 wavelengths and slope variations of more than 400 wavelengths/diameter. Comparisons are made with results of Twyman-Green interferometric tests for wavefront aberrations of up to thirty wavelengths. The results indicate that small wavefront aberrations can be measured as accurately with the lateral-shear interferometer as with the Twyman-Green interferometer and that aberrations that cannot be measured at all with a Twyman-Green interferometer can be measured to about 1% accuracy or better.

A Ronchi ruling is photographed through a phase object that deforms the grating lines. The object is displaced longitudinally, and a second exposure is made. After developing, the photographic plate is observed with a frequency-plane mask that cuts off all but one of the diffracted orders. A lateral-shear interferogram of the phase object is obtained in this way. The experiment may be carried out by making multiple exposures and by displacing the object through equal distances after each exposure. This will produce a multiple-beam lateral-shear interferogram, and the fringes become very sharp.

The results of a parametric study of torsional coupling effects in the response of asymmetric buildings to a grouped selection of 45 strong motion earthquakes from Europe, North America, the Middle East and Southern Pacific are presented. The period dependency of the key response parameters is studied in relation to the site dependent criteria employed by certain earthquake-resistant design codes for specifying the lateral shear forces to be resisted by the structural frames and/or walls. Unlike lateral forces, the torsional response is relatively insensitive to the ration of peak ground accelaration to velocity, which has been used in previous studies as a measure of the effect on earthquake ground motions of site soil conditions and epicentral distance. The results show that the effect of torsional coupling on edge displacement response is more pronounced in stiff, short period structures. However, the dynamic shear and torque responses are relatively insensitive to variations in structural period. Codified design provisions for torsional effects specified in the United States, Canadian and European seismic building regulations are assessed, along with alternative proposals, in relation to the analytical results. It is concluded that in some cases special provisions are needed for short period asymmetric systems, a feature which has been neglected by the codes and inadequately accounted for in previous proposals.

These relationships have been developed keeping in mind force-based design. For this reason, they provide low estimates of period such that the lateral shear force is conservatively predicted from an acceleration spectrum. On the contrary, in displacement-based assessment, the displacement demand is required, being better correlated to the expected damage. This displacement would be underestimated using the aforementioned period-height formulae (Crowley and Pinho, 2004).

This excerpt gives a succinct explanation of rotating grating lateral shear interferometer, Savart plates, and Wollaston prisms.

In this report, lens testing method for small lenses is discussed. Cylindrical or aspherical lenses are included to the scope of this report in addition to spherical lenses. A shearing interferometer is applied for the measurement. That consists of a plane parallel plate for inducing lateral shear for the test beam. This method is robust to disturbances because it is a common path interferometry. Moreover it is not necessary to prepare reference lens. For these reasons it can be said that this method is practical and is good for using at actual factories.

Reinforced concrete (R/C) cylindrical panels have been applied to the roof or the underground structures. Also, in constructing a high rise building, an R/C wall is often used to improve the lateral rigidity of the building comparing with beam column systems under wind or seismic loading. In this paper, the behavior of R/C cylindrical shell under combined axial and lateral shear loadings is analyzed numerically. R/C cylindrical shells are often adopted for the core wall system. R/C cylindrical panels are fixed at both hoop edges and are subjected to a lateral shear displacement after axial compressive load is applied in the meridional direction. In numerical analyses, the behavior of R/C cylindrical shell panel is analyzed under several combinations of axial and lateral loadings. The panels are modeled by use of the shell elements.

A wedge plate interferometer has been constructed using holo optical elements (HOEs). It comprises of two HOEs namely a Holo Shear Lens (HSL) and a Holo Shear Tilt Lens (HSTL). The combined effect of the two is to introduce a lateral shear and a tilt between the sheared wavefronts, the tilt beign orthogonal to the shear direction. This is equivalent to the conventional shear itnerferometer using a wedge plate for collimation testing. Theory and experimental results are presented.

This paper evaluates the earthquake-resistant design provisions of the 1990 edition of the National Building Code of Canada (NBCC 1990) for asymmetric building structures subjected to combined lateral shear and torsional dynamic loadings arising from earthquake base excitation. A detailed parametric study is presented, evaluating the dynamic edge displacement response in the elastic range, for the side of the building which is adversely affected by lateral–torsional coupling. A series of buildings is studied, with realistic ranges of the fundamental natural period, structural eccentricity, and uncoupled frequency ratio. These buildings are evaluated under base loadings arising from a total of 45 strong motion records taken from earthquakes in North America, Mexico, Europe, the Middle East, and Southern Pacific, categorized according to site soil conditions and the ratio a/v of peak ground acceleration to velocity. The latter parameter together with the uncoupled lateral period are found to influence strongly the combined dynamic edge response, with the greatest forces on edge members arising from earthquakes with high a/v ratio in structures with natural periods below 0.8 s. In this case the NBCC 1990 loading provisions significantly underestimate the elastic dynamic response. For buildings with periods longer than 0.8 s, the conservatism of the base shear provisions leads to overestimation of combined dynamic edge response in asymmetric systems, and this is also true in the short-period range for buildings subjected to ground motions with low a/v ratio. The NBCC 1990 provisions are reasonably conservative for short-period systems subjected to ground motions with intermediate a/v ratio. Key words: earthquakes, seismic, design, response, spectra, base, shear, torsional, provisions.

The equations developed in Riskowski and Friday (1991) and included in ASAE EP 486 (ASAE, 1991) were used to evaluate the sensitivity of post foundation strengths to various combinations of embedment depths, post sizes, collar and footing sizes, and soil strengths. These equations were also used to compare predicted lateral and vertical load resistances of post foundations to field research results. Moment capacity of nonconstrained post foundations was found to be sensitive to changes in lateral shear. Collars and attached footings significantly increased lateral strength and vertical uplift resistance of post foundations. Predictions were conservative relative to field test values for the nonconstrained post-only, nonconstrained bottom collared posts with rock and gravel backfill, and con-strained bottom collared posts. The predicted values for nonconstrained bottom collared posts with soil backfill were significantly under field test values. All predicted uplift resistances were much lower than field test values.

Damage to gypsum wallboard can be an indicator of the level of lateral movement experienced during an earthquake. A series of 17 experiments conducted at San Jose State University recorded common failure modes of gypsum wallboard typical of construction in woodframe structures. These experimental tests showed the relationship between lateral movement of the ceiling and floor and the type and extent of the resulting damage. This knowledge can be used to make field judgments about the level of movement that may have resulted during an earthquake or other severe lateral loading. This paper will review the damage thresholds observed during the experimental testing and the fragility curves developed for each damage threshold. BACKGROUND Gypsum wallboard has a wide variety of uses in modern construction. The primary purpose of wallboard is the interior surface for wood framed walls or ceilings in residential construction. Wallboard is often used as the interior finish surface on vertical surfaces of commercial and institutional construction, often supported by steel studs. The primary purpose of wallboard is to provide a durable surface for architectural finish. In addition wallboard on bearing walls is expected to provide buckling stability for the framing. In certain situations, wallboard may be considered the lateral force resisting system for the structure. In addition, wallboard may be a significant part of the fire control system of the structure. In the past, research has been conducted on the lateral shear strength of wallboard systems, particularly those with small spacing between fasteners, thus qualifying their use as a portion of the lateral force resisting system [Merrick 1997, Karacabeyli and Ceccotti 1996, Oliva 1990; Zacker and Gray 1985, Adams, 1974]. This paper focuses on the role of wallboard as an architectural finish for vertical walls, particularly those built on wood framing for single-family residential construction. Of particular interest is the damage of the wallboard due to lateral forces applied at the top level. Damage patterns of wallboard are related to interstory drift and the potential use of damage patterns as a means of assessing potential damage to underlying structural members is discussed. As a result of this focus, most of the discussion is related to the visible damage to wallboard. Additional information about the testing and physical properties of wallboard research conducted by the authors is available in other publications [McMullin and Merrick, 2007, 2002].

A novel method for testing the collimation of coherent optical beam is presented. Two prisms are used to define a thin air wedge with a wedge angle. A wide range of beam sizes can be tested down to a few millimeters in diameter. By redirecting the transmitted beam back to the air wedge so that it experiences a shear in the reversed direction, a double-shearing interferometry can be established. The gap separation and wedge angle can be varied to maintain high sensitivity (twice that of the wedge plate design) over the wide beam size range.

A two-dimensional, finite difference numerical model is used to describe longitudinal transport through a transverse cross section into and out of the northern segment of Indian River lagoon, along the Atlantic coast of Florida. The model uses four layers to represent the Atlantic Intracoastal Waterway, and two layers in the shallow waters east and west of the waterway to quantify transport. Simulations during a 161-day period from late June through late November 1983 include a seasonal shift in the longitudinal component of the wind. Transport is in the same sense throughout the cross section 32% of the time. Relatively subtle lateral shear, however, has a profound effect on long-term net transport. For most of the study, cumulative net transport in the shallow areas on either side of the waterway follows the cumulative along-channel windstress, but it is directed upwind in the lower half of the Intracoastal Waterway. Four numerical experiments examine the relative importance of terms in the momentum equation and components of the database. Results suggest that time-varying baroclinic forcing is an important component of the pressure gradient. Simulations which ignore water-level variations at the open end of the model differ substantially from those which incorporate water-level fluctuations.

Twelve subjects participated in an investigation of the biomechanical stresses of asymmetric lifting in stooped and kneeling postures. Three factors were manipulated in this study: Posture (stooped or kneeling), height of lift (35 or 70 cm), and weight of lift (15, 20, or 25 kg). Subjects were required to lift or lower a box every 10 seconds for a period of 2 minutes. Electromyography (EMG) of eight trunk muscles was collected during a lift in this period. The EMG data, normalized to maximum extension and flexion exertions in each posture, were input to a biomechanical model and used to predict compression and shear forces at the L3 level of the lumbar spine. Results from the EMG-driven biomechanical model indicated that compression was greater when lifting to a higher shelf (p < 0.001), and indicated a significant interaction between posture and the weight of the lifting box (p < 0.01). Peak lateral shear was not significantly affected by any main effects or interactions (p < 0.05). Anterior shear was increased with increasing height of lift (p < 0.001), and also by the posture x weight interaction (p < 0.01). A multivariate analysis of variance (MANOVA) indicated a complex relationship for recruitment of the eight trunk muscles, with the triple interaction being significant (p < 0.001). The results of this investigation will be used to evaluate safe loads for lifting in these restricted postures.

The lower St Lawrence Estuary is an interesting case amongst estuaries in that it is wide enough to accommodate the development of mesoscale unstable waves and eddies. These features are generated by the runoff‐driven jet along this body's south shore. We present data yielding estimates of the length, time and velocity scales of these unstable disturbances. To relate these quantities to the dynamics we employ a 2‐layer quasigeos‐trophic instability model featuring realistic lateral shear. All model runs show short time and length scales, e‐folding periods of less than 10 days and wavelengths less than 50 km.

We present a shear interferometer that is based on an air wedge placed in the Fourier domain of a 4f-configuration as the shearing element. The two images are formed by the reflections from the front and reverse surfaces of the wedge. Due to a lateral displacement of the reflected beams in the Fourier domain, the interference pattern in the sensor domain is modulated by carrier fringes. Hence, the system is capable of single shot operation. The great advantage of this configuration over already existing shearing setups that make use of air wedges is that the shear can be set independently from the carrier modulation.

Background The last several years have seen an increased interest in elucidating the causes of non-traumatic injuries specific to bicyclists. Injuries may include soreness of the pelvis, skin problems in the groin, erectile dysfunction, and impotence. Combined loading at the seat may be contributing factors to these injuries. Methods Vertical and shear loads were collected for 10 subjects cycling at 75 crank revolutions per minute (RPM) in a common fit position. External workload was held constant at 125 watts while force data were collected using a multi-axis load cell integrated under the seat of a standard bicycle. The crank arm angles at which the maximum forces occurred were obtained using a motion analysis system, and regions of rider contact with the seat were visualized with a pressure mapping system. Findings Measured vertical loads at the seat were greater than shear loads. Maximum mean vertical loads of 49–52% body weight, rearward shear loads of 11–12% body weight, and lateral shear loads of 4–5% body weight occurred at the seat. Associated timing angles referenced to the pedal position were also measured and averaged at the maximum and minimum loads. Interpretation Seat pressure mapping and blood flow have previously been used to study the interaction between bicyclists and their seats. This investigation focused on shear and vertical seat loads that may be contributing factors in injuries at the groin.

Human intervertebral disc specimens were tested to determine the regions of largest maximum shear strain experienced by disc tissues in each of three principal displacements and three rotations, and to identify the physiological rotations and displacements that may place the disc at greatest risk for large tissue strains and injury. Tearing of disc annulus may be initiated by large interlamellar shear strains. Nine human lumbar discs were tagged with radiographic markers on the endplates, disc periphery and with a grid of wires in the mid-transverse plane and subjected to each of the six principal displacements and rotations. Stereo-radiographs were taken in each position and digitized for reconstruction of the 3-D position of each marker. Maximum tissue shear strains were calculated from relative marker displacements and normalized by the input displacement or rotation. Lateral shear, compression, and lateral bending were the motions that produced the mean (95% confidence interval) largest regional maximum shear strains (MSS) of 9.6 (0.7) %/mm, 9.0 (0.5) %/mm, and 5.8 (1.6) %/° respectively, and which occurred in the posterior, posterolateral and lateral peripheral regions of the disc. After taking into account the reported maximum physiological range of motion for each degree of freedom, motions producing the highest physiological MSS were lateral bending (57.8 (16.2)%) and flexion (38.3 (3.3)%), followed by lateral shear (14.4 (1.1)%) and compression (12.6 (0.7)%).

In this paper we investigate the generation of shear strain elastograms induced using a lateral shear deformation. Simulation and experimental results demonstrate that the shear strain elastograms obtained under shear deformation exhibit significant differences between bounded and unbounded inclusion phantoms, when compared to shear strain images induced upon an axial compression. A theoretical model that estimates the decorrelation between preand post-deformation radiofrequency signals as a function of the shear deformation quantified by the lateral shear angle is also developed. Signal-to-noise ratios of shear strain elastograms obtained at different shear angles are investigated theoretically and verified using ultrasound simulations on a uniformly elastic phantom. Our results indicate that the signal-to-noise ratios of shear strain images increases to reach a maximum and then decreases with increasing shear angle. Shear strain elastograms obtained experimentally using single inclusion tissue-mimicking phantoms with both bound and unbound inclusions (mimicking cancerous masses and benign fibroadenomas respectively) demonstrate the characteristic differences in the depiction of these inclusions on the shear strain elastograms

The purpose of this study was to determine the characteristics of eighteen lumbar spine motion segments subjected to lateral shear forces under quasi-static (0.5 mm/s) and dynamic (500 mm/s) test conditions. The quasi-static test was also performed on the lumbar spine of a side impact anthropomorphic test device, the EuroSID-2 (ES-2). In the quasi-static tests, the maximum force before disc-endplate separation in the PMHS lumbar motion segments was 1850 +/- 612 N, while the average linear stiffness of PMHS lumbar motion segments was 323 +/- 126 N/mm. There was a statistically significant difference between the quasi-static (1850 +/- 612 N) and dynamic (2616 +/- 1151 N) maximum shear forces. The ES-2 lumbar spine (149 N/mm) was more compliant than the PMHS lumbar segments under the quasi-static test condition. Language: en

[1] The Indochina peninsula has been hypothesized to be in the Sunda block, a rigid block in SE Asia. However, its northern boundary is not obvious. To elucidate the boundary and the deformation on the peninsula, six permanent GPS sites were established in Thailand, and observations have been conducted since March 1998. Estimated velocities suggest that most of the Indochina peninsula is rigid and can be considered in the Sunda block. However, close examination suggest small but significant strain in the order of 10−8 exists in Thailand. Statistical test suggests that there is no significant differential motion between the Sunda block and the South China block. On the other hand, acute clockwise rotation of east Himalayan syntax indicates left lateral shear in the north of Thailand, which may be partially accommodated by left lateral motion along Mae Chan fault.

Barchan dunes are found where sand availability is low and wind direction quite constant. The two dimensional shear stress of the wind field and the sand movement by saltation and avalanches over a barchan dune are simulated. The model with one dimensional shear stress is extended including surface diffusion and lateral shear stress. The resulting final shape is compared to the results of the model with a one dimensional shear stress and confirmed by comparison to measurements. We found agreement and improvements with respect to the model with one dimensional shear stress. Additionally, a characteristic edge at the center of the windward side is discovered which is also observed for big barchans. Diffusion effects reduce this effect for small dunes.

A new optical phase retrieval algorithm by lateral shear interferometer with wavelet transform is introduced. It can reconstruct the smooth wavefront faster than conventional polynomial fit. And to rough wavefront function, it also can do better. The computer simulation is also given.

Optical manufacturing facilities are often limited by the size of the optics they can interferometrically measure. This paper describes three practical methods to increase the aperture of interferometric surface coverage. These methods include a lateral shear, a subaperture rotational stitching routine and a through-the-element test.

To quantify the variability in lifting motions, trunk moments, and spinal loads associated with repeated lifting exertions and to identify workplace factors that influence the biomechanical variability.Measurement of trunk dynamics, moments and muscle activities were used as inputs into EMG assisted model of spinal loading.Traditional biomechanical models assume repeated performance of a lifting task produces little variability in spinal load because the assessments overlook variability in lifting dynamics and muscle coactivity.Five experienced and seven inexperienced manual materials handlers performed 10 repeated lifts at each combination of load weight, task asymmetry and lifting velocity.Box weight, task asymmetry and job experience influenced the magnitude and variability of spinal load during repeated lifting exertions. Surprisingly, experienced subjects demonstrated significantly greater spinal loads and within-subject variability in spinal load than inexperienced subjects. Trial-to-trial variability accounted for 14% of the total variation in compression overall and 32% in lateral shear load. Although the mean spinal load was safely below the NIOSH recommended limit; due to variability about the mean, more than 20% of the lifts exceeded the recommended limit.Spinal load changed markedly from one exertion to the next despite identical task requirements. Trial-to-trial variability in kinematics, kinetics, and spinal load were influenced by workplace factors, and may play a role in the risk of low-back pain.Ergonomic assessments considering only the mean value of spinal load overlook the fact that a large fraction of the lifts may exceed recommended levels.

Abstract The performance of more than 3,000 offshore platforms in the Gulf of Mexico was observed during the passage of Hurricane Andrew in August 1992. ?IMs event provided an opportunity to test the procedures used for platform analysis and design. A global bias was inform for overall platform capacity and loads in the Andrew Joint Industry Project (JIP) Phase 1.1 It was predicted that the pile foundations of several platform should have failed, but did not. ?lime results indicated that the biases specific to foundation failure modes may be higher than those of jacket failure modes. ?Ile biases in predictions of foundation failure modes were therefore investigated further in this study. ?he work included capacity analysis and calibration of predictions with the observed behave for 3 jacket platforms and 3 caissons using Bayesian updating. Bias factors for two foundation failure mess, lateral shear and overturning, were determined feat structure. Foundation capacity estimates using conventional methods were found to be conservative y biased overall. Introduction Hurricane Andrew was a very intense storm that passed through the Gulf of Mexico in August 1992. While most of the Gulf of Mexico platforms were not adversely affected by Andrew, twenty eight steel jacket platforms were significantly damaged. All of these were installed during 1948 to 1969 and were located in water depths up to 143 feet. In addition, forty seven caissons, nstalled during 1979 to 1991 in water depths up to 113 feet, were also significantly damaged. While foundation failure was identified as the primary cause of damage to most caissons, it was identified as the cause for damage of only one steel jacket platform. An extreme event such as Andrew provides a unique opportunity to study offshore structures tested under fill scale field conditions. By reviewing the platforms that survived, were damaged or failed during the hurricane it is possible to improve our understanding of the behavior of platform during large storm. In October, 1993, Phase I of a joint industry project, "Hurricane Andrew - Effects on Offshore Platforms,''1'3 was completed. This project established that there was bias in the safety factor (capacity to load ratio) by combining the analytical and observed behavior of 13 jacket platforms. The inform bias is characterized as a correction needed to bring analytical results to agreement with the observed results. The capacity analysis performed in Phase I of the Andrew JIP indicated that failure of foundation elements should have occurred in a majority of platforms analyzed, Since this was not observed during post-Andrew inspections, it was concluded that the deterministic analysis was conservatively biased. An overall (system) correction factor, with a mean of 1.2 was established. This correction factor was not specific to any particular failure mode in the jacket structure m its foundation but rather included failures of all types.

The form of the wave front of powerful iodine laser ISKRA-5 having an aperture of 700 mm has been investigated using a lateral shear interferometer. Results of determining the optical system aberrations and the monopulse WF form are presented.© (1994) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

A novel method is presented for one-dimensional wavefront recovery on the basis of difference measurements from two shearing interferograms with varying tilt. The method uses large shears and obtains high lateral resolution. Furthermore, the wavefront under test can be recovered exactly up to an arbitrary constant and straight line at all evaluation points with suitably chosen shears of two shearing interferograms.

International audience; Right-lateral shear along the eastern margin of Asia, from the Eocene to the Present has led to the opening of pull-apart basins, intracontinental such as the Bohai basin, or oceanic such as the Japan Sea. We suggest in this paper that this right-lateral shear is a consequence of indentation of Asia by India. As in small-scale analog experiments, we conclude that antithetic wrench faults accommodate the counterclockwise rotation of large domino blocks between two major left-lateral shear zones (Tien Shan-Baikal-Stanovoy for the northern one, and Qin Ling for the southern one). We discuss the compatibility of this mechanism, which involves a rather small amount of extrusion, with the fast eastward expulsion described for southeast Asia. We re-emphasize the role played in the opening of marginal basins by the Pacific subduction as a free boundary to the east.

A method for obtaining interference patterns of increased sensitivity in optical processing of holographic lateral shear interferograms recorded under linear conditions at a shear exceeding the size of a phase object under study is proposed. Cases of reconstruction of interference patterns of increased sensitivity using matched and optically conjugate holographic lateral shear interferograms are considered. It is shown that two-and fourfold increases in sensitivity, respectively, are obtained in these cases. The validity of the method proposed is confirmed experimentally