Insights worth sharing

Motives for better Engineering

Coulomb's wedge theory
of earth pressure

Explore horizontal earth pressure,
Coulomb's theory, and its applications.
Compare geotechnical results and
understand the trial wedge method's nuances.

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Baltimore bridge collapse:
What structural engineers can do

Explore the technical content on vessel collision
to calculate the annual frequency of bridge component collapse.

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Seismic Isolation in Structural Design:
Concepts and Applications

Introducing the concept of seismic isolation design.

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System Method for P-Delta Effects

Y.S LeeJun 03, 2024

Understanding the Impact of Insertion Points and Beam End Release

Luis VilaNov 08, 2023

For structures with stability issues, one way to check which specific link is causing the problem is start with a constrained model and begin relaxing its DOFs gradually. When you are releasing the DOFs and when you are running into stability issues, you would know which link release is causing that instability. 

Decoding Pushover Analysis: Insights on Seismic Design

Yong YangOct 20, 2023

With more users asking us questions regarding pushover analysis and its applications in midas Civil, we want to share the answers to some of these common questions to our user community. Hopefully, this would help you understand pushover analysis in midas Civil environment a little more, and we want you to be more confident when using midas Civil to perform seismic design and analysis. We invited one of our Midas experts Yong Yang, principal structural engineer from Jacobs, to share some of his experience regarding those questions.

The Challenges: Design and Construction of Irregular Bridges

Percy PenafielOct 20, 2023

There are times when engineers would have to design and evaluate bridge structures that fall outside of the AASHTO design guideline. Therefore, when do we define a structure as irregular? How is evaluating an irregular bridge different from evaluating a regular bridge? How to minimize errors during the construction of irregular bridges? We invited midas expert Percy Penafiel, Professional Engineer Specialist from Nevada Department of Transportation, to answer some of the frequently asked questions from our users regarding evaluating irregular bridge structures. 

 

Unlocking Advanced Structural Analysis: Warping Stress in Midas

Yazeed AbuHassanOct 20, 2023

In typical engineering practices, engineers are used to having six degrees of freedom (DOFs) for modeling and analysis, three for rotations and three for translation. However, additional advanced beam elements can include other DOFs to represent the warping of an open thin-walled cross section. Such elements are not commonly available in professional software. (Article 1.2.6, G13.1 Guidelines for Steel Girder Bridge Analysis, AASHTO/NSBA, 2014). This has required engineers to model flanges as plates in order to obtain warping stresses. Midas Civil on the other hand has the 7th DOF warping feature which should save engineers a lot of time and effort and can grant warping related results directly from frame elements. 

Bridge Design: Post-Tensioning for the New Fulton Street Arch Bridge

Daniel BaxterOct 20, 2023

In the design project to replace the old Fulton Road arch bridge in Cleveland, OH, Michael Baker Intl engineer Daniel Baxter and his team has designed a 1,568-foot-long replacement structure for the original arch bridge, which retains the original design of six 210-foot-long concrete deck arch spans. For the replacement bridge structure, a precast, post-tensioned concrete arch bridge design was selected. You may be asking yourself, why post-tensioning the arch bridge? Arches usually provide sufficient stabilities to structures and it is not usual for bridge designers to post-tension such structures. In this tip, Daniel Baxter talks about why his team has decided to post-tension the arch bridge and how they have utilized construction stage analysis to design the post-tension process. 

Understanding Time Dependent Material in Prestressed Concrete

Benjamin BlasenOct 20, 2023

When we talk about prestressed concrete, the things that we are mostly concerned about are the compressive strength gain with respect to time, and the prestressing tendon relaxation with respect to time. Figure 1 shows various time-dependent effects for concrete including creep and shrinkage.

 

The factors that affect the creep rate include water/cement ratio, age and strength of the concrete when it is subjected to stress, and ambient temperature and humidity. Creep rate also depends on many other factors related to the quality of the concrete and conditions of exposure such as the type, amount, and maximum size of aggregate; type of cement; amount of cement paste; size and shape of the concrete mass; amount of steel reinforcement; and curing conditions (Robert Salca, tech support, midas UK).

 

For shrinkage, its rate decreases much faster with time compared with creep as shown in figure 1. Finer aggregates and finer gels result in increased shrinkage, the moisture content of the concrete and the relative humidity of the ambient medium have a big influence on carbonation shrinkage, and harder aggregates with higher modulus of elasticity decrease shrinkage. 

Balancing Safety and Efficiency: Strategies for Bridge Load Posting

Yanling LengOct 20, 2023

Bridge load posting – identifying just how much weight a bridge can bear – is a matter of public safety and a way to safeguard vital transportation infrastructure. However, load posting is less straightforward than it may seem. Not posting a bridge can create safety issues for the motoring public, while posting makes transportation more difficult for large, heavy vehicles and the industries that use them. 

Composite Bridge Modeling Tips: A Comprehensive Guide

Zachary TaylorOct 20, 2023

How to Model the Girder and Deck Connection in Composite Bridge?

 

The way to simulate the connection between the girder and the deck will depend on how we construct the model. In the 2D all-frame composite bridge model shown in Figure 1, all the elements are connected in the grid within the same plane. Because it was modeled with the "all frame" model type in the midas Civil composite bridge wizard, it only consists of a 2-D grid frame composed of beam elements. In this scenario, the software considers the composite section as a lump section that incorporates both the girder section and the deck section. This means that the composite action is transformed into equivalent section properties in midas Civil. 

Understanding Convergence in Curved Girder Analysis

What is Convergence? What is a Convergence Study? 

 

It is easy to obtain the result from bridge finite element analysis, but to get more accurate results requires extra effort. Even the most robust finite element analysis solvers adopt the method that approximates the structural behavior, by minimizing the associated error function compared with the complex function that represents the realistic structural behavior. 

Strut-and-Tie Modeling for Pier Caps: Geometries and Practices

Daniel BaxterOct 20, 2023

What is Strut-and-Tie Analysis? What are "Struts" and "Ties" in Strut-and-Tie Analysis?

 

Streamlined Shear Design for Steel Composite Girders

Believe it or not, once upon a time, there were no computers available for us, bridge engineers. At that time, we had to perform every calculation by hand using calculators or even slide-rules. It was quite dull and time-consuming. Now all we have cutting-edge computers, which is way better than those we used when we landed at the Moon. Everything looks nice, and life seems beautiful, doesn't it?

Michael Baker's Approach to Complex Load Rating for Steel Bridges