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The majority of offshore wind turbines are founded on large-diameter, open-ended steel monopiles. Monopiles must resist lateral loads and overturning moments because of environmental (wind and wave) actions, whereas vertical loads tend to be comparatively small. Recent developments in turbine sizes and increases in hub heights have resulted in pile diameters increasing rapidly, whereas the embedment length to diameter ratio (L/D) is reducing. Soil erosion around piles, termed scour, changes the soil strength and stiffness properties and affects the system's load resistance characteristics. In practice, design scour depths of up to 1.3D are routinely assumed during the turbine lifetime; however, the impact on monopiles with low L/D is not yet fully understood. In this article, centrifuge tests are performed to assess the effect of scour on the performance of piles with low L/D. In particular, the effect of combined loads, scour type (global, local), and depth are considered. A loading system is developed that enables application of realistic load eccentricity and combined vertical, horizontal, and moment loading at the seabed level. An instrumented 1.8-m-diameter pile with L/D = 5 is used. A friction-reducing ball-type connection is designed to transfer lateral loads to the pile without inducing any rotational pile-head constraint, which is associated with loading rigs in tests of this nature. Results suggest that vertical and lateral load interaction is minimal. Scour has a significant impact on the lateral load-bearing capacity and stiffness of the pile, leads to increases in bending moment magnitude along the pile shaft, and lowers the location of peak pile bending moment. The response varies with scour type, with global scour resulting in larger moments than local scour. The size of the local scour hole is found to have a significant impact on the pile response, suggesting that scour hole width should be explicitly considered in design.

The influence of scour on the lateral response of monopile foundations for offshore wind turbines is investigated in this paper. Application of lateral load-displacement (p-y) curves to predict the lateral pile behaviour is subject to uncertainty as many of the presently used design approaches have been derived for long, slender piles. These piles, with typical length/diameter ratios (L/D) of greater than 10 behave differently compared to rigid monopiles, with L/D typically less than 6. In this paper, centrifuge tests are conducted on a monopile model under various scour scenarios and p-y curves are derived from strain gauges embedded along the model pile wall. Global scour and two different shapes for local scour holes are studied. Using the piecewise polynomial method for extraction of p-y curves from sparsely distributed strain measurements, it is recommended to use a 4th order polynomial for the moment profile to extract soil reaction and a 7th order polynomial for the moment profile to calculate pile deflection. Results indicate that the pile behaviour is significantly influenced by the nature (size, shape) of the scour holes affecting the pile–soil system and suggest that the p-y curves should be appropriately modified to account for this behaviour.

Study Design. Systematic review. Objective. To investigate the prognostic value of clinically induced changes in spinal symptoms (i.e., symptom response) in the conservative management of spinal pain. Summary of Background Data. Symptom response is used by clinicians to inform management decisions. Understanding the prognostic value of symptom response can aid in this decision-making process. Methods. A search of Ovid-Medline, Ovid-Embase, Ovid-Cinahl, Ovid-Amed, reference lists and citation tracking was performed. Methodologic quality was assessed independently by 2 raters. Results. We included 22 articles reporting 18 different cohorts. The evidence was limited and mainly involved low back pain. We found no association between most symptom responses and clinical outcomes. Only for changes in pain location and/or intensity with repeated spinal movement testing or as a response to treatment did the data provide support for use of symptom response to inform management. Further work is needed to confirm these findings. Limited evidence of an association with disability was found for the prone instability test in low back pain patients attending a stabilization program. The evidence for neurodynamic testing was conflicting for low back pain. The strength of identified associations and the extent of confounding between investigated prognostic factors remain uncertain. Conclusion. Further investigation of symptom responses in spinal pain is needed before their use can be recommended.

Evaluation of the use of exercise in the management of anterior disc displacement of the temporomandibular joint is currently lacking. A review of the literature was undertaken which showed that although therapeutic exercise may be of value for outcome measures such as pain, functional impairment and joint sounds, there is insufficient evidence to establish its efficacy in the management of anterior disc displacement. Furthermore, the methods of exercise treatment provision and the types of exercise which are most beneficial to this group of patients need to be established. Further studies including large, well-designed, randomised, controlled trials are needed to determine the clinical utility of this management approach in anterior disc displacement of the temporomandibular joint.