190,247 research outputs found
Species composition and catch per unit of effort of Monterey Bay surf, pier, and skiff anglers in 1979
In 1979, Monterey Bay sport anglers were sampled for species
composition of the catch and catch per unit of effort. A total of 4150 surf, pier, and skiff anglers was interviewed. Catch per hour was 0.71, 0.58, and 1.25 for surf, pier, and skiff anglers, respectively. Barred surfperch, Amphisticus argenteus, totaled 76% of the surf catch. The species composition of the pier catch was dominated by juvenile bocaccio, Sebastes paucispinis; white croaker,
Genyonemus lineatus; and walleye surfperch, Hyperprosopon argenteum. The skiff fishery was dominated by sanddabs, Citharichthys spp., and blue rockfish, Sebastes mystinus. The best surf fishing area was between Palm Beach and Sand Dollar Beach in northern Monterey Bay, while Monterey Wharf No. 2 was the best public fishing pier. However, a small privately operated pier inside Moss Landing Harbor had the best catch rate (2.44 fish per h) of all piers sampled. (23pp.
Stochastic Ray Propagation in Stratified Random Lattices â Comparative Assessment of Two Mathematical Approaches
In this report, ray propagation in stratified semi-infinite percolation lattices consisting of a succession of uniform density layers is considered. The final version of this article is available at the url of the journal PIER: http://www.jpier.org/PIER
Southern California pier fishermen: how familiar are they with the sport fishing regulations?
Anglers frequently violate sport fishing regulations out
of ignorance, by mistake, or by deliberate action. To
determine whether unfamiliarity with the regulations plays
a major part in this problem, we asked pier fishermen a
series of questions which tested their knowledge of the
regulations.
We discovered that on any given weekday, only 7% of the
anglers on a pier kept a copy of the regulations with
them for reference. The remaining fishermen had to depend
upon memory for the rules; however, only 31% of the anglers
knew three or more of those rules.
Pier anglers are not well-enough informed to follow the
size limit regulations. However, anglers on piers do not
often catch size-regulated fish . Unless these anglers
engage in another type of fishing (such as from a boat)
they will not significantly detract from the success of
fishery management programs for size-regulated fish species. (8pp.
Centrifuge modeling of rocking-isolated inelastic RC bridge piers
Experimental proof is provided of an unconventional seismic design concept, which is based on deliberately underdesigning shallow foundations to promote intense rocking oscillations and thereby to dramatically improve the seismic resilience of structures. Termed rocking isolation, this new seismic design philosophy is investigated through a series of dynamic centrifuge experiments on properly scaled models of a modern reinforced concrete (RC) bridge pier. The experimental method reproduces the nonlinear and inelastic response of both the soil-footing interface and the structure. To this end, a novel scale model RC (1:50 scale) that simulates reasonably well the elastic response and the failure of prototype RC elements is utilized, along with realistic representation of the soil behavior in a geotechnical centrifuge. A variety of seismic ground motions are considered as excitations. They result in consistent demonstrably beneficial performance of the rocking-isolated pier in comparison with the one designed conventionally. Seismic demand is reduced in terms of both inertial load and deck drift. Furthermore, foundation uplifting has a self-centering potential, whereas soil yielding is shown to provide a particularly effective energy dissipation mechanism, exhibiting significant resistance to cumulative damage. Thanks to such mechanisms, the rocking pier survived, with no signs of structural distress, a deleterious sequence of seismic motions that caused collapse of the conventionally designed pier. © 2014 The Authors Earthquake Engineering & Structural Dynamics Published by John Wiley & Sons Ltd
Legal Context for Construction of Bristol Veterans\u27 Home Universally-Accessible Fishing Pier
This study reviews the legal requirements governing design and construction of a proposed universally-accessible fishing pier located at the Rhode Island Veteransâ Home in Bristol, Rhode Island. The pier would provide veterans and other members of the public with accessible recreational fishing opportunities. However, federal, state, and local approvals will be required before the project can move forward. This study provides an overview of required permitting and approvals by the Coastal Resources Management Council (CRMC), Town of Bristol, and U.S. Army Corps of Engineers (USACE). In addition, it considers the role of the Rhode Island Department of Environmental Management (RIDEM) and federal Americans with Disabilities Act (ADA)
FOOTING FIXITY EFFECT ON PIER DEFLECTION
The rotational restraint coefficient at the top of a pier and the rotational restraint coefficient at the bottom of the pier (that is, the degree of fixity in the foundation of the pier) are used to determine the effective length factor of the pier. Moreover, the effective length factor of a pier is used to determine the slenderness ratio of the pier, while the degree of fixity in the foundation of a pier is used to perform the first-order elastic analysis in order to compute the pier deflection. Finally, the slenderness ratio of the pier is used to determine if the effect of slenderness shall be considered in the design of the pier, while the magnitude of the pier deflection resulting from the first-order analysis is used to determine if the second-order force effect (the p-â effect) shall be considered in the design of the pier. The computations of the slenderness ratio and the deflection of a pier, however, have conventionally been carried out by assuming that the base of the pier is rigidly fixed to the footing, and the footing in turn, is rigidly fixed to the ground. Other degrees of footing fixity have been neglected by the conventional approach. In this paper, two examples are demonstrated for the slenderness ratio computation and the first-order deflection analysis for bridge piers with various degrees of footing fixity (including footings anchored on rock, footings not anchored on rock, footings on soil, and footings on multiple rows of end-bearing piles) recommended by the AASHTO LRFD Bridge Design Specifications. The results from the examples indicate that the degree of footing fixity should not be neglected since it significantly affects the magnitude of the slenderness ratio and the deflection of the pier
Countermeasure of Scour around Pier in Steady Current
The experiments on the countermeasures of scours around pier in steady current were conducted in this paper. The factor formations of scour were identified by extensive research of previous paper that related to the project. Scour formations were influence by the strength of the flow, the size of pier, and the sediment condition. From the literature, the project invented a few innovative pier protection measures which are single cross-threaded pier and double-cross threaded pier with variation of cable diameter and thread angle. These cross-threaded piers also tested with collar protection. As the result, the single cross-threaded piers and double cross-threaded piers able to reduce scour in average of 18% and 21% respectively. While, single cross-threaded piers with collar and double cross-threaded piers with collar able to reduce scour in average of 69% and 63% respectively. The single cross-thread pier with collar of 0.1 cable-pier diameter ratio and 15° thread angle outperforms other models with scour reduction of 79%. That shows the cable-pier diameter ratio and thread angle influent the performance of models in scour reduction. The large number of cross-threaded pier with large cable-pier diameter ratio and small thread angle will give the best performance in reducing potential formation of scour depth
Reduction in wind force in relation to corner design of bridge piers
The effects of wind on beam bridges can be significantly reduced with careful design of deck, roadway and wind barriers, as well as with appropriate design of piers. In this paper, the influence of corner design of rectangular cross-sectional piers to total wind force on piers is investigated. The total wind force changes, due to a different corner design of rectangular cross section of piers in free standing phase, are analyzed for piers of different heights, different environments and different wind velocities. The correlation between changes in total wind force and changes in geometric properties of a pier is also shown. By rounding the corners of a pier square cross section, the total wind force on pier in free standing phase can be drastically reduced in comparison to the total wind force on sharp corner pier with a small reduction in a load bearing properties of the pier. Changes in the bridge pier environment, as well as changes in pier height and wind velocity have negligible influence on changes in reduction of total wind force due to rounding the pier corners
Gabion basket for reducing scour around a rectangular bridge pier
Riprap, a slit inside the pier, a number of piles located in front of a pier, collars, and other strategies have all been used to control scouring around bridge piers. In this study, a new alternative countermeasure for reducing scour around the rectangular bridge pier was investigated. A gabion basket âa stone basket attached to the upstream face of the pierâwas investigated experimentally for reducing scouring depth around the bridge pier as a countermeasure in a clear-water condition. For estimating the efficiency of using the stone basket as a countermeasure for reducing scour, the scour findings of the pier with no modifications were used as a basis for comparison. The findings indicate that the pier using a stone basket significantly reduced the scour depth. According to the findings, the pier with a stone basket size of dg/B = 0.3 lowered the depth of scouring to 50%, and the best relative length of the stone basket was Lg/B = 0.5. Based on the experimental findings, a formula for predicting scour depth at rectangular bridge piers was developed. The results of this study may be used in the field of application for bridge pier protection design
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