Monthly webinars

February 28, 12:00 p.m. – 1:00 p.m. CT

Cast in Place Segmental Success at LAX with Form Travelers

Presenters:
Nabil Bouabid, Head of Strategic Projects, PERI Formwork Systems, Inc.
Pawel Okolowicz, Project Manager, PERI Formwork Systems, Inc.

Registration Link

You must attend the entire 60 minute presentation in order to receive the PDH certificate.

Abstract

Join us for an exciting presentation as we showcase PERI, a leading international formwork, scaffolding, and construction engineering company. With our expertise in balanced cantilever bridge construction, we have successfully completed projects around the globe, including our latest venture into the North American market. During this session we will unveil our inaugural project in the United States, the LAX Automatic People Mover project, highlighting the innovative ideas and advancements that set PERI apart as a specialized formwork company. Our focus will extend beyond the superstructure scopes of the bridge project as we introduce our suite of solutions for other critical elements of segmental bridge projects including piers, pier tables, and end spans. Our aim is to demonstrate how PERI brings unparalleled value to segmental bridge projects through state-of-the-art solutions, cutting-edge technologies, and willingness to solve complex processes for our customers on their projects. By pushing the boundaries of the industry, we are committed to advancing the field and redefining the possibilities of formwork.

March 27, 12:00 p.m. – 1:00 p.m. CT

Monitoring the Closure Segment of Post-Tensioned Box Bridges Constructed with the Balanced Cantilever Method

Presenter:
Alp Caner, WSP

Registration Link

You must attend the entire 60 minute presentation in order to receive the PDH certificate.

Abstract

Balanced cantilever construction method for post-tensioned box bridges necessitates precise deflection control of the cantilever sections. This is crucial to minimize any construction discrepancies when connecting the two ends prior to pouring the closure segment. Once the closure segment concrete has been placed and hardened, bottom slab post-tensioning will be conducted while flexing the traveler form at certain times to accommodate the changes in mid-span displacements. Throughout the years, it has come to light that the bottom slab of segmental bridges is susceptible to early cracking, particularly in the vicinity of closure segment locations during the post-tensioning of the bottom slab. This phenomenon has been usually attributed to the tensioning of curved tendons within the curved bottom slab. The curvature of the bottom slab exerts restraint on tensioned tendons, causing them to adopt a curved form instead of a natural linear form. In scenarios like this, local stresses, often overlooked during the designer’s global stress analysis of the structure, can augment the overall stresses at specific points. A method to preempt such failures involves the installation of strain-gauged rebars prior to pouring the closure segment’s bottom slab. Ordinarily, this bottom slab is subject to post-tensioning in multiple stages until all the tendons are stressed in a predetermined sequence. In two separate construction instances, the employed monitoring system yielded successful outcomes, having undergone an assessment of the concrete stresses within the bottom slab after each tendon tensioning. Moreover, further applications of strain-gauged rebars will be explored, including their utilization in the fabrication of precast prestressed girders and for detecting live loads in steel truss bridges.

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