Background: Age-related changes in pelvic floor muscle (PFM) biomechanics may contribute to urinary incontinence in older women; however, empirical evidence is scant. Purpose: This study aimed to understand the age-related changes in the biomechanical properties of the PFMs in women with no major risk factors for urinary incontinence. Methods: Thirty-three nulliparous women (20-64 years) were recruited to study active force, rate of force development, endurance, resistance to passive stretch and stiffness properties of the PFMs using an automated dynamometer. Separate regression analyses were performed to investigate the relationship between age and each outcome measure. Results: No significant relationships were observed between age and any of the outcome measures. Conclusion: The findings from this study do not support the presence of any age-related changes in PFM mechanics among women aged 20-64. Recruiting women over the age of 65 may be essential to detect age-related changes in PFM biomechanics in nulliparous women.

Passive detrusor smooth muscle exhibits both viscoelastic softening and strain softening. Strain softening is a loss of stiffness following a stretch to a longer length and is reversible upon muscle activation. Because of this behavior, steady state passive force in detrusor is not constant for a given muscle length and can be adjusted by an intracellular mechanism. Thus, passive detrusor exhibits adjustable passive stiffness. Existing three-component mechanical models for muscle, the Kelvin and Voigt, are insufficient to display this characteristic. The goal of this thesis is to develop a new biomechanical model for passive force in detrusor by adding additional elements to the Kelvin or Voigt models. Eight mechanical characteristics of detrusor are identified from the literature and with three new experiments, and a novel adjustable passive stiffness model for smooth muscle is proposed. Simulations are performed to demonstrate that the model qualitatively exhibits each of the eight tissue characteristics.

Although its use has become more widespread, controlled low-strength material, or CLSM, has fallen through the crack between geotechnical engineering and materials engineering research. The National Ready Mix Association states that CLSM is not a low strength concrete, and geotechnical engineers do not consider it as a conventional aggregate backfill. The use of CLSM as a bridge abutment backfill material brings up the need to understand the passive force versus backwall displacement relationship for this application. To safely account for forces generated due to seismic activity and thermal expansion in bridge design, it is important to understand the passive force versus backwall displacement relationship. Previous researchers have pointed out the fallacy of designing skewed bridges the same as non-skewed bridges. They observed that as the bridge skew angle increases, the peak passive force is significantly diminished which could lead to poor or even unsafe performance. The literature agrees that a displacement of 3-5% of the wall height is required to mobilize the peak passive resistance. The shape of the passive force displacement curve is best represented as hyperbolic in shape, and the Log Spiral method has been confirmed to be the most accurate at predicting the peak passive force and the shape of the failure plane. All of the previous research on this topic, whether full-scale field tests or large-scale laboratory tests, has been done with dense compacted sand, dense granular backfill, or computer modeling of these types of conventional backfill materials. However, the use of CLSM is increasing because of the product's satisfactory performance as a conventional backfill replacement and the time saving, or economic, benefits. To determine the relationship of passive force versus backwall displacement for a CLSM backfilled bridge abutment, two laboratory large-scale lateral load tests were conducted at skew angles of 0 and 30°. The model backwall was a 4.13 ft (1.26 m) wide and 2 ft (0.61 m) tall reinforced concrete block skewed to either 0 or 30°. The passive force-displacement curves for the two tests were hyperbolic in shape, and the displacement required to reach the peak passive resistance was approximately 0.75-2% of the wall height. The effect of skew angle on the magnitude of passive resistance in the CLSM backfill was much less significant than for conventional backfill materials. However, within displacements of 4-5% of the backwall height, the passive force-displacement curve reached a relatively constant residual or ultimate strength. The residual strength ranged from 20-40% of the measured peak passive resistance. The failure plane did not follow the logarithmic spiral pattern as the conventional backfill materials did. Instead, the failure plane was nearly linear and the failed wedge was displaced more like a block with very low compressive strains.

Low-strength cellular concrete is a type of controlled low-strength material (CLSM) which is increasingly being used for various modern construction applications. Benefits of the material include its ease of placement due to the ability of cellular concrete to self-level and self-compact. It is also extremely lightweight compared to traditional concrete, enabling the concrete to be used in fill applications as a compacted soil would customarily be used. Testing of this material is not extensive, especially in the form of large-scale tests. Additionally, effects of skew on passive force resistance help to understand performance of a material when it is used in an application where skew is present. Two passive force-deflection tests were conducted in the structures lab of Brigham Young University. A 4-ft x 4-ft x 12-ft framed box was built with a steel reaction frame on one end a 120-kip capacity actuator on the other. For the first test a non-skewed concrete block, referred to as the backwall, was placed in the test box in front of the actuator. For the second test a backwall with a 30° skew angle was used. To evaluate the large-scale test a grid was painted on the concrete surface and each point was surveyed before and after testing. The large-scale sample was compressed a distance of approximately three inches, providing a clear surface failure in the sample. The actuator provided data on the load applied, enabling the creation of the passive force-deflection curves. Several concrete cylinders were cast with the same material at the time of pouring for each test and tested periodically to observed strength increase.The cellular concrete for the 0° skew test had an average wet density of 29 pounds per cubic foot and a 28-day compressive strength of 120 pounds per square inch. The cellular concrete for the 30° skew test had an average wet density of 31 pounds per cubic foot and a 28-day compressive strength of 132 pounds per square inch. It was observed from the passive force deflection curves of the two tests that skew decreased the peak passive resistance by 29%, from 52.1 kips to 37 kips. Various methods were used to predict the peak passive resistance and compared with observed behavior to verify the validity of each method.

Two series of static full-scale lateral pile cap tests were conducted on pile caps with different aspect ratios, with full width (homogeneous) and limited width backfill conditions involving loose sand and dense gravel. The limited width backfills were constructed by placing a relatively narrow zone (3 to 6 ft (0.91 to 1.83 m)) of higher density gravel material adjacent to the cap with loose sand beyond the gravel zone. Test results indicated that large increases in lateral passive resistance could be expected for limited width backfills. The main focus of this study is to assess the contribution of plane strain stress effects and 3D geometric end effects to the total passive resistance mobilized by limited width backfills, using soil and pile cap properties associated with the field tests. For this purpose, the finite element program, PLAXIS 2D was used to investigate the static plane strain passive behavior of the full-scale tests. To validate the procedure, numerical results were calibrated against analytical results obtained from PYCAP and ABUTMENT. The analytical models were additionally validated by comparison with measured ultimate passive resistances. The calibrated model was then used to simulate the passive behavior of limited width gravel backfills. Parametric studies were also executed to evaluate the influence of a range of selected design parameters, related to the pile cap geometry and backfill soil type, on the passive resistance of limited width backfills. Numerical results indicated that significant increases in passive resistance could be expected for long abutment walls where end effects are less pronounced and the geometry is closer to a plane strain condition. Comparisons between measured and numerical results indicated that using the Brinch-Hansen 3D correction factor, R3D, as a multiplier to the plane strain resistances, will provide a conservative estimate of the actual 3D passive response of a pile cap with a limited width backfill. Based on results obtained from the parametric studies, a design method was developed for predicting the ultimate passive resistance of limited width backfills, for both plane strain and 3D geometries.

Large scale static lateral load tests were completed on a pile cap with wingwalls under several different sand backfill configurations: no backfill, loosely compacted unconfined, loosely compacted slip plane wall confined, loosely compacted MSE wingwall confined, and densely compacted MSE wingwall confined. The relative compaction of the backfill was varied during each test to observe the change in passive resistance provided by the backfill. The wall types were varied to observe the force placed on the walls and the wall displacement as a result of the laterally loaded pile cap and backfill relative compaction. Passive force-displacement curves were generated from each test. It was found that the densely compacted material provided a much greater passive resistance than the loosely compacted material by 43% (251 kips) when confined by MSE walls. The outward displacement of the MSE walls decreased noticeably for the dense MSE test relative to the loose MSE test. Backfill cracking and heave severity also increased as the relative compaction level of the backfill increased. As the maximum passive force was reached, the reinforcement reached their peak pullout resistance. Correlations were developed between the passive pressure acting on the pile cap and the pressure measured on the MSE wingwalls as a function of distance from the pile cap for both loose and dense backfills. The pressure measured on the wingwalls was approximately 3 to 9% of the pressure acting on the pile cap. As the distance from the pile cap increased, the pressure ratio decreased. This result helps predict the capacity of the wingwalls in abutment design and the amount of allowable wall deflection before pullout of the backfill reinforcement occurs. Three methods were used to model the measured passive force-displacement curves of each test. Overall, the computed curves were in good agreement with the measured curves. However, the triaxial soil friction angle needed to be increased to the plane strain friction angle to accurately model both the loose and dense sand MSE and slip plane wall confined tests. The plane strain friction angle was found to be between 9 to 17% greater than the triaxial friction angle.

Large scale static lateral load tests were performed on a pile cap under varying sand backfill configurations: no backfill, full-width dense sand backfill, dense sand slip plane confined backfill, and two configurations of dense sand MSE wall confined backfills. Efforts were made to maintain the relative compaction of the backfills for each of the tests near the same value. The MSE wall panel arrangement was varied to determine the effect of different reinforcement configurations on the passive resistance and wall panel displacement. Passive force-displacement curves were generated from each test. It was found that the MSE design manual provided reasonable estimates of pullout resistance of bar mats in dense sand, and that the passive resistance of a soil backfill confined by MSE walls can be calculated with an increased friction angle using a log-spiral approach. Also, the amount the triaxial friction angle can be increased depends on how much the MSE wall panels displace outward. Correlations were developed between the pressure on the pile cap and that on the MSE wall panels near the pile cap. Generally, the pressure on the wall panels was less than 10% of that which was on the adjacent pile cap, and decreased as the distance from the pile cap increased. Finally, it was found that while limiting the backfill width decreases the ultimate passive resistance of the backfill, if the backfill is confined in a plane strain configuration the passive resistance per unit width is higher than that for an unconfined backfill.

Accounting for seismic forces and thermal expansion in bridge design requires an accurate passive force versus backwall deflection relationship. Current design codes make no allowances for skew effects on the development of the passive force. However, small-scale experimental results and available numerical models indicate that there is a significant reduction in peak passive force as skew angle increases for plane-strain cases. To further explore this issue large-scale field tests were conducted at skew angles of 0°, 15°, and 30° with unconfined backfill geometry. The abutment backwall was 11 feet (3.35-m) wide by 5.5 feet (1.68-m) high, and backfill material consisted of dense compacted sand. The peak passive force for the 15° and 30° tests was found to be 73% and 58%, respectively, of the peak passive force for the 0° test which is in good agreement with the small-scale laboratory tests and numerical model results. However, the small differences may suggest that backfill properties (e.g. geometry and density) may have some slight effect on the reduction in peak passive force with respect to skew angle. Longitudinal displacement of the backfill at the peak passive force was found to be approximately 3% of the backfill height for all field tests and is consistent with previously reported values for large-scale passive force-deflection tests, though skew angle may slightly reduce the deflection necessary to reach backfill failure. The backfill failure mechanism appears to transition from a log spiral type failure mechanism where Prandtl and Rankine failure zones develop at low skew angles, to a failure mechanism where a Prandtl failure zone does not develop as skew angle increases.

This dissertation thesis focuses on the evaluation of modern machine tools, especially tools for finishing operations, with which the effect of the passive force components on the machining process is evaluated. The thesis will examine the analysis of creating chips and circumstances that accompany this process and substantially involve the formation of a new surface. The analysis of the process of the recording of the power load of the MT3 tool takes place in the experimental part of the thesis. MT3 is a reaming head intended for finishing holes at high cutting speeds (100-200 m.min-1) with removal of small cross section AD (0.024 mm2) chips. Particular attention is paid to the newly created profile from the surface after machining and evaluation of changes in geometry and loading of the cutting edge, which is significantly reflected in the establishment and the development of passive forces.

Low-strength cellular concrete consists of a cement slurry that is aerated prior to placement. It remains a largely untested material with properties somewhere between those of soil, geofoam, and typical controlled low-strength material (CLSM). The benefits of using this material include its low density, ease of placement, and ability to self-compact. Although the basic laboratory properties of this material have been investigated, little information exists about the performance of this material in the field, much less the passive resistance behavior of this material in the field.In order to evaluate the use of cellular concrete as a backfill material behind bridge abutments, two large-scale tests were conducted. These tests sought to better understand the passive resistance, the movement required to reach this resistance, the failure mechanism, and skew effects for a cellular concrete backfill. The tests used a pile cap with a backwall face 5.5 ft (1.68 m) tall and 11 ft (3.35 m) wide. The backfill area had walls on either side running parallel to the sides of the pile cap to allow the material to fail in a 2D fashion. The cellular concrete backfill for the 30<&degree> skew test had an average wet density of 29.6 pcf (474 kg/m3) and a compressive strength of 57.6 psi (397 kPa). The backfill for the 0<&degree> skew test had an average wet density of 28.6 pcf (458 kg/m3) and a compressive strength of 50.9 psi (351 kPa). The pile cap was displaced into the backfill area until failure occurred. A total of two tests were conducted, one with a 30<&degree> skew wedge attached to the pile cap and one with no skew wedge attached.It was observed that the cellular concrete backfill mainly compressed under loading with no visible failure at the surface. The passive-force curves showed the material reaching an initial peak resistance after movement equal to 1.7-2.6% of the backwall height and then remaining near this strength or increasing in strength with any further deflection. No skew effects were observed; any difference between the two tests is most likely due to the difference in concrete placement and testing.