Dimensional Analysis of Compound Section in The Regulate Section Channel Model for Maintenance Main Channel

A dimensionless number is used to express the relationship between parameters and is used to describe the research results. Commonly used dimensional analysis methods are the Basic Echelon method, the Buckingham method, the Rayleight method, the Stepwise method and the Langhaar method. The compound section in the regulated section channel model aims to make the section convenient to the flow existing discharge at tidal conditions, in sediment flushing. In this study using the Buckingham’s method of dimensional analysis to determine the weight equation for the flushing sediment (w) and the variables that have been scaled on the flume, W = • (B, B*, h, h*, ⊗h, t, V, Q, g, W,)w,)S), where B is the width of the river (cm), B* is the width of the Flushing section (cm), h is the height of the water level (cm), h* is the height of the flushing section (cm), ®h is the difference in water level (cm), t is the tidal time period (s), V is the flow velocity (cm/s), Q is the water discharge (cm3/s), g is the gravity (cm/s2), )S is the mass density of the sediment (gr/cm3), )w is the density of the water mass (gr/cm3). From the analysis results obtained equations = B * B . h * h . Δ h h . v g t . Q g h 2 t . ρ s h 3 . Where w is the weight of the flushing sediment (gr), B * B is the ratio of the design cross-sectional width to the width of the estuary, h * h is the ratio of the flushing cross-sectional height to the water level, Δ h h is the ratio of the height water level to water depth, v g t is the velocity of falling sediment, Q g h 2 t is the discharge of sediment flushing, ρ s h 3 is the hydrostatic pressure.

Formation and Failure Mechanism of the Xinfangzi Landslide in Chongqing City (China)

At 2:00 a.m. on 1 July 2020, after several days of continuous heavy rainfall, the Xinfangzi landslide occurred in Zhengping Village, Ganshui Town, Qijiang District, Chongqing City, China. The area of the landslide was about 3.85 × 104 m2 and the volume was about 71.22 × 104 m3. The Xinfangzi landslide can be defined as a push-type landslide. Specifically, the main sliding area pushed the front squeezing area, causing it to slide laterally. The entire slip path of the landslide was a broken line, while the right edge and the front shear outlet position slipped loosely in a circular arc. In this study, finite element numerical calculations were used to compare and analyze the multisection plastic deformation of the landslide under natural and rainfall conditions based on field investigations. The formation and failure characteristics of the Xinfangzi landslide were further revealed. The results show that the cross and longitudinal sections of the landslide were in a critical state of instability under natural and rainfall conditions. A compound section was established along the slip path based on the cross and longitudinal sections. Due to the extrusion of the trailing edge of the landslide, the compound section’s leading edge was in a state of instability under natural conditions. Under rainfall conditions, the increase in the unit weight of the sliding mass was superimposed on the compound section, which amplified the thrust of the trailing edge and further accelerated the overall sliding process of the landslide. Based on the macroscopic deformation of the landslide, it was found that the sliding of the trailing edge of the landslide is the key factor promoting the failure of the front edge, and local slump is possible under rainfall conditions.

Stress-deformation state of compound reinforced concrete bars with high-strength reinforcement prone to long-term compression

Introduction. Considering that reinforced concrete is the most common material in construction and reconstruction of buildings and facilities, research of work of high-strength reinforcement in reinforced concrete elements, including compressed columns, are still relevant at present. Analysis of compound-section columns with high-strength longitudinal reinforcement is of particular interest since the method of sectional build-up is widespread enough in the reconstruction of buildings and facilities. However, no information on the work of this kind of reinforced concrete structures under long-term compression was found either in foreign or domestic literature; this fact provides relevance and academic novelty of the study. Materials and methods. The article provides the research of parameters of the strain-stress state of compound reinforced concrete bars with high-tensile reinforcement under long time compression employing the modern methods of mathematical simulation. Results. The developed calculation method allows determining additional parameters of the strain-stress state of the compressed compound-section reinforced concrete bars considering the concrete creep deformations forming in time of the long-term compression. When comparing the analytical study results with authors’ experimental data and previous results of other researchers, an adequate degree of reliability of the developed calculation method was confirmed. Conclusions. When applying the developed calculation method of stress-deformation state parameters for the compressed compound-section columns with high-strength longitudinal reinforcement, the study discovered that significant effort redistribution from concrete to high-strength reinforcement occurs under long-term compression. This fact was confirmed with the results of an experimental investigation on the resistance of the compound reinforced concrete bars with high-tensile reinforcement to the longtime compression.

New Compound Open Channel Section with Polynomial Sides: Improving Cost and Aesthetics

Previous research on compound trapezoidal cross sections has mainly focused on improving the prediction of the discharge (flow rate) because of its inherent challenges. This paper focuses on two other important aspects: Section shape and optimal construction cost. First, the paper proposes a new compound section with third-degree polynomial sides of main channel with horizontal bottom (HB) that allows its top corners to be smooth, called herein compound polynomial section. The special cases of this versatile section include the simple polynomial section, polygonal section, trapezoidal-rectangular section, two-segment linear-side section, and parabolic bottom-trapezoidal section. The simple polynomial section, which is the bank-full part of the compound polynomial section, can further produce parabolic (with or without HB), trapezoidal, rectangular, and triangular sections. Second, an optimization model that minimizes construction cost (excavation and lining) of the compound (or simple) polynomial section is developed. The model includes discharge and physical constraints. Theoretical and empirical methods of discharge prediction were used in the model. The results show that the simple polynomial section was more economical than the popular parabolic section by up to 8.6% when the side slopes were restricted. The new polynomial-based sections not only reduced construction cost, but also improved maintenance and aesthetics. As such, the new sections should be of interest to researchers and practitioners in hydraulic engineering.

Advances in Experimental Study on Seismic Performance of Double C Steel Joints with Gusset Plate

It requires higher seismic performance of buildings. Double C steel structures with gusset plate have better seismic performance than general concrete structures and steel structures, and few studies have looked at its bending joints. Through the experimental analyses on seismic performance of Double C steel joints with gusset plate, we get the conclusion that this type of joints have high bending capacity, stable strength degradation, obvious initial stiffness degradation, good energy dissipation and ductility, and look forward to the development and application prospect of this compound section.

The Program Design of the Variable Cross-Section of Concrete Continuous Skew Beam Bridge

In practical engineering, we often encounter designs of variable cross-section or compound section skew girder bridge. While in many bibliographies, uniform cross-section of the concrete beams studying was carried out, but few of variable cross-section concrete beams were in-depth studied. Based on analyzing the mechanical behavior of variable cross-section beam skew girder bridge, the semi-analytic solution of variable cross-section beam skew girder bridges were provided in this paper. With this method developed a planar computation program to resolve the calculation problems of skew girder bridge, a more convenient way will be brought up for designers in calculation.

Experimental and computational study of velocity fields in narrow or compound section sewers

Sound management of sewer networks and minimization of the pollution discharged into receiving waters through combined sewer overflows need in-depth knowledge of the flow rates and pollutant loads conveyed in sewers. This knowledge relies on a good assessment of the spatial distribution of the velocities in a cross section, as they are involved both in flowrate, and distribution of concentration. The possibility of assessing this distribution by using computational fluid dynamics is explored and compared with experimental results collected from real sewers.