Performance Evaluation of Open Graded Base Course with Doweled and Non-Doweled Transverse Joints

The objectives of this study were to investigate the performance of 20-year old doweled/non-doweled and dense-graded/permeable base test sections on three concrete pavement segments in Wisconsin: USH 18/151 in Iowa and Dane counties, STH 29 in Brown County, and USH 151 in Columbia and Dane Counties. Five pavement bases were placed including: dense graded, asphalt-stabilized permeable, cement-stabilized permeable, and untreated permeable having two gradation sizes. USH 18/151 test sections had similar performance (PDI) for doweled unsealed pavement on dense and permeable base. Distresses common to all segments included slight to moderate distressed joints/cracks and slight transverse faulting. Asphalt-stabilized permeable base had no slab breakup or surface distresses, however it measured a greater severity of distressed joints and cracks. Non-doweled sections having asphalt-stabilized permeable base and Transverse Inter Channel drains had better performance and ride than the other non-doweled sections. IRI was generally higher on non-doweled pavements, but many doweled sections had an equal roughness to non-doweled sections. Sealed non-doweled joints produced a better performing pavement, however, sealant did not appear to improve ride. STH 29 unsealed sections performed better than the median PDI for the sealed sections. The sealed doweled pavement did perform a little better than the non-doweled section, but the opposite occurred on the non-doweled sections. Sealed doweled joints had a smoother ride than the other combinations. USH 151 test sections found the finer-graded New Jersey permeable base had the smoothest ride when compared to other permeable sections. Asphalt-stabilized permeable base had the roughest ride, and unstabilized and cement-stabilized permeable bases had intermediate values. The average hydraulic conductivity for the unstabilized permeable base was 17,481 feet per day and there appears little variation due to doweling or joint sealant. Deflection load transfer results indicate expected high average values for the doweled sections and fair to poor values for the non-doweled sections. Slab support ratios indicate variable results based on base type and joint reinforcement/sealant. Life-cycle cost analysis found dense-graded base was the least cost among all base alternatives, with a total estimated present-worth life-cycle cost of $665,133 per roadway mile. Untreated and asphalt-stabilized permeable bases were more expensive by 13% and 27%, respectively. Other factors in selecting dense-graded base over permeable base include project drainage conditions set forth in the FDM guidelines an anticipated increase in pavement surface roughness

Tests on a CAST 7 two-dimensional airfoil in a streamlining test section

A unique opportunity has arisen to test one and the same airfoil model of CAST-7 section in two wind tunnels having adaptive walled test sections. The tunnels are very similar in terms of size and the available range of test conditions, but differ principally in their wall setting algorithms. Detailed data from the tests of the model in the Southampton tunnel, are included with comparisons between various sources of data indicating that both adaptive walled test sections provide low interference test conditions

Concrete - filled steel tube columns - tests compared with Eurocode 4

This paper summarises the data from 1819 tests on concrete-filled steel tube columns and compares their failure load with the prediction of Eurocode 4. The full data is given on the website http://web.ukonline.co.uk/asccs2 . The comparison with Eurocode 4 is discussed and shows that Eurocode 4 can be used with confidence and generally gives good agreement with test results, the average Test/EC4 ratio for all tests being 1.11. The Eurocode 4 limitations on concrete strength could be safely extended to concrete with a cylinder strength of 75 N/mm2 for circular sections and 60 N/mm2 for rectangular sections

Testing for Unit Roots in Nonlinear Dynamic Heterogeneous Panels

In this paper we present a unit root test against a nonlinear dynamic heterogenous panel with each cross section modelled as an LSTAR model. All parameters are viewed as cross section specific. We allow for serially correlated residuals over time and heterogenous variance among cross sections. The test is derived under three special cases: (i) the number of cross sections and observations over time are fixed, (ii) observations over time are fixed and the number of cross sections tend to infinity, and (iii) first letting the number of observations over time tend to infinity and thereafter the number of cross sections. Small sample properties of the test show modest size distortions and satisfactory power being superior to the Im, Pesaran, and Shin t-type of test. We also show clear improvements in power compared to a univariate unit root test allowing for nonlinearities under the alternative hypothesis.Dynamic nonlinear heterogenous panels; Structural breaks; Unit roots; t-statistics; Central limit theorem;

Thermocouple-flexible cable connector insulator is highly reliable

Plastic /polycarbonate/ insulator improves thermocouple reliability in test operations. The insulator is molded in half sections, assembled mechanically and eliminates electrical shorting

Selective tube roughening increases heat transfer capability

Selectively roughening inside surfaces of tubes increases the heat transfer capabilities, but minimizes the pressure drop. This technique is used to construct roughened test sections for hydrogen heat transfer studies

Influence of Stirrup-Tie Shape on Inelastic Cyclic Response of Flanged Reinforced Concrete Flexural Members

Three reinforced concrete flanged sections (T-sections) having different shapes of shear reinforcement were subjected to cyclic inelastic flexure representative of what framed structure members might-be forced to endure during a severe earthquake. The different types of shear reinforcement consisted of closed hoops and two types of U-shaped stirrups, neither having been supplemented with cap ties. This report documents the experimental work, presents data obtained during tests (including energy dissipation capacities) and discusses the implications of test results on possible changes in reinforcement details for frame structures in seismic regions