Interactive Panel Proceedings - Iowa State University...the Pulaski Skyway, a 3.5 mile-long viaduct that links Newark, NJ with Jersey City, NJ. Altogether, 118 spans and 1 million

Interactive Panel Proceedings from the

First International Interactive Symposium on Ultra-High Performance Concrete

July 18-20, 2016

Des Moines, Iowa, USA

INTERACTIVE PANEL 2 UHPC for Bridges, Part 1:

UHPC for ABC Connections

Panel Chair: Benjamin Graybeal, Ph.D., P.E., Federal Highway Administration Expert Panel Members:

Mathew Royce, P.E., New York State Department of Transportation

Michael McDonagh, P.E., P.Eng., WSP/Parsons Brinckerhoff

Jeffrey A. Hanlon, President - Slate Hill Constructors, Inc.

Bendt Aarup, R&D Manager - Hi-Con A/S

Panel Interactivity Administrator: Interactive Panel Synopsis Report Zachary Haber, Ph.D., GENEX Systems Authored by: Zachary Haber Benjamin Graybeal

First International Interactive Symposium on Ultra-High Performance Concrete, July 18-20, 2016 2

Interactive Panel 2: UHPC for Bridges Part 1 - UHPC for ABC Connections

Chaired by Benjamin Graybeal from the Federal Highway Administration (FHWA), this interactive panel on the use of ultra-high performance concrete (UHPC) for Bridges was comprised of experts from the FHWA, the New York State Department of Transportation (NYSDOT), WSP/Parsons Brinckerhoff, Slate Hill Constructors and Hi-Con A/S. Discussions covered definitions, experiences and the status of UHPC connections for bridge construction and other applications. Panel 2, Part 1, "UHPC for Bridges: UHPC for ABC Connections", began with the following introductory presentation by Dr. Graybeal. (Panel 2, Part 2, addressed "The Future of UHPC in Bridges".)


Prior to opening the interactive portion of this session, short presentations were delivered by each panel member to provide background and motivate audience questions. Panel names, affiliations and presentation titles are listed below: 1. Benjamin Graybeal, FHWA: Overview of the Status and Direction - pg. 3

2. Mathew Royce, NYSDOT: NYSDOT Perspective on UHPC Connections - pg. 6

3. Michael D. McDonagh, WSP/Parsons Brinckerhoff: Design Consultant’s Perspective

- pg. 7

4. Jeffrey A. Hanlon, Slate Hill Constructors, Inc.: Construction of UHPC Connections - pg. 8

5. Bendt Aarup, Hi-Con A/S: European Experience with UHPC Connections - pg. 9 This State-of-the-Art Report provides copies of each presentation, along with brief summaries. The transcribed questions from the interactive session are provided in Appendix A.

1. Presentation by Benjamin Graybeal: Overview of the Status and Direction



Dr. Graybeal’s presentation provided context and background related to the use of UHPC in bridge construction and connections between prefabricated bridge elements. He began with an introduction to various UHPC applications for the bridge sector and followed with a discussion as to why UHPC has emerged as a viable option, explaining some of the materials' beneficial properties. He then presented where UHPC has been used for bridge construction in the US and Canada (Figure 1) and noted that the majority of deployments to date include the use of UHPC for connections between prefabricated bridge elements.

Figure 1. Location of bridges in the US and Canada that employ UHPC (as of Spring 2016). The remainder of this presentation focused on two areas: the differences between conventional and UHPC connections for prefabricated bridge elements and; different connection types that have been recently deployed and/or others that are now being investigated under the FHWA structural concrete research program. In conclusion, Dr. Graybeal informed the audience about currently available FHWA resources related to the design and construction of field-cast UHPC connections.

Note: Two bridges in northern Alberta are not shown


2. Presentation by Mathew Royce: Perspective on UHPC Connections

Mr. Royce’s presentation highlighted different types of UHPC connections that have been deployed by the New York State Department of Transportation (NYSDOT) including: deck-to-deck; deck-to-girder; connections between adjacent deck-girder elements; precast barriers; semi-integral backwalls; and joint-eliminating link slabs. Mr. Royce subsequently discussed previous projects that utilized the afore-mentioned connections. Examples are shown in Figure 2.

(a) Precast deck panel connections (b) Connections between adjacent deck bulb tee elements Figure 2. Example connections.


3. Presentation by Michael McDonagh: The Design Consultant’s Perspective

Mr. McDonagh’s presentation focused on UHPC connections from a design consultant’s perspective. Specifically, he shared his experience with an ongoing project that is utilizing prefabricated bridge deck panels with deck-to-deck and deck-to-girder UHPC connections. The project is a complete re-decking of the Pulaski Skyway, a 3.5 mile-long viaduct that links Newark, NJ with Jersey City, NJ. Altogether, 118 spans and 1 million square feet of bridge deck will be replaced during the course of the project. Mr. McDonagh discussed: key details; types of UHPC connections being used; quality control measures taken prior to and during the construction process; and construction-related challenges. Figure 3 shows representative photos from the Pulaski Skyway project.

(a) Precast deck panel placement (b) Close-up of deck-to-deck connection Figure 3. Representative photos from the Pulaski Skyway UHPC Connections Project.


4. Presentation by Jeffrey A. Hanlon: Construction of UHPC Connections

Mr. Hanlon’s presentation provided context on bridge projects that employ UHPC connections from the contractor's prospective. In particular, Mr. Hanlon discussed his experience with a recent project in Syracuse, NY. The 72 foot span, 4 lane bridge on the I-690 over Crouse Avenue required a complete deck replacement on an expedited construction schedule. Deck removal began on a Friday at noon and was quickly replaced using prefabricated deck panels with UHPC connections. The bridge re-opened on the following Monday at noon. Also discussed was the key aspects and primary challenges of the project including: demolition of the existing deck; preparation of girders for new deck installation; installation of prefabricated deck panels; UHPC connection formwork; mixing; placement and curing of UHPC; and deck grinding. Figure 4 shows representative photos from the I-690 over Crouse Avenue project.

(a) Demolition of existing bridge deck (b) Prefabricated deck panels awaiting UHPC placement Figure 4. Representative photos from the I-690 over Crouse Avenue project.


5. Presentation by Bendt Aarup: European Experience with UHPC Connections

Mr. Aarup’s presentation touched on different types of UHPC connection projects completed in different parts of Europe over the last 20 years. Discussions covered initial applications of UHPC connections in prefabricated building construction during the mid-1990s and more recent applications such as prefabricated staircases and wind turbine towers. In conclusion, Mr. Aarup highlighted UHPC connection applications for prefabricated highway and pedestrian bridges. Figure 5 shows photos of the Catharina Bridge in Holland, constructed with 8 prefabricated segments connected with UHPC.

(a) Connection of prefabricated elements (b) Completed bridge Figure 5. Construction of the Catharina Bridge, Holland.


Summary of Panel-Audience Interaction Two interactive polls were completed using an app-based interactive platform prior to interactive discussions between the audience and panel members. Poll 1 determined audience affiliation while Poll 2 determined audience involvement with UHPC projects. Figure 6 shows the results from these polls and total number of votes collected.

Poll 1 - Question: What is your affiliation? (27 Votes)

Poll 2 - Question: Have you been directly involved with the deployment of UHPC on an active or completed project? (32 Votes)

Figure 6. Poll 1 and 2 response results: Part 1.

During the one-hour interactive panel discussion, 43 questions were submitted by the audience using the app-based interactive platform. Twenty-nine questions were then shared with the moderator, and in some cases modified or edited in order to combine multiple, similar questions. In general, the questions could be categorized into 1 of 9 categories: construction; cost; connections and detailing; past performance; codification; material availability; material properties, testing, research; other; or not relevant. Figure 7 reveals the percentage of questions asked within each category. Much of the discussion focused on the construction of UHPC connections and addressed specific questions regarding connection design and detailing. (See "Appendix A".) Upon completion of the interactive session, attendees were asked to rate their level of interest (from 1-5) with respect to the potential integration of UHPC into their toolbox of solutions. For example, a rating of 1 would indicate “not interested” and 5 would indicate “very interested”. Out of 22 votes collected, 72% responded with a 5. Ratings of 4 and 3 received 9.1% and 18.2% of the votes, respectively. There were no votes for ratings below 3.

44.4%

29.6%

11.1%

3.7%

11.1%

Owner:

Federal:

Consultant:

Industry/ Supplier:

Academia:

65.6%

34.4%

YES

NO


Figure 7. Summary of types of questions asked by the audience in Part 1.

23.3%

4.7%

23.3%

14.0%

4.7%

2.3%

11.6%

11.6%

4.7%

ConstructionOther

Cost

Connections& DetailingPast Performance

Codification

Material Availability

Not Relevant

Materials Properties, Testing, Research


APPENDIX A – Interactive session

Below is a list of question categories and examples, as addressed by the following panel experts.

Mathew Royce, New York State Department of Transportation

Michael McDonagh, WSP/Parsons Brinckerhoff

Jeffrey A. Hanlon, Slate Hill Constructors, Inc.

Bendt Aarup, Hi-Con A/S

Chair: Dr. Benjamin Graybeal, FHWA

Question Category Example Question

Construction What best practices do you recommend to prevent forms from blowing out? How do you enforce the water-tightness of formwork?

Cost Do contractors realize cost and time savings after they have completed a few projects?

Connections & Detailing

How do you create the exposed aggregate finish on precast deck panels? Does it really help bond? Is it really needed?

Past Performance What is the performance history for completed projects in the US and Europe?

Codification Has change to the development length for rebar in the AASHTO code affected the development length for rebar in UHPC?

Material Availability Have any states used non-proprietary UHPC in recent deployments? Or; are commercial products always used?

Material Properties, Testing, Research

What types of QC/QA field testing are required or needed during placement?

Other Did NYSDOT receive any public complaints regarding the patchwork appearance of the new bridge deck?

Not Relevant Will the PowerPoint presentations be available to attendees?


Questions Likes

Passed to

Moderator

Is there a recommended bearing type (fixed or expansion) for use

with the link slab detail that NYSDOT is using?

8 YES

Do contractors see advantages relative to conventional construction

methods? 7 YES

What best practices do you recommend to prevent forms from blowing out?

How do you enforce the water-tightness of formwork? 7 YES

Can UHPC be pumped or does it have to be placed with carts or buckets? 7 YES

Do you have recommendations for accommodating super elevations

with the pouring of the UHPC? 6 YES

What is the performance history for completed projects in the US and

Europe? 5 YES

Has any work been done to investigate the influence of shear key shape

on deck connection performance? 5 YES

Has change to the development length for rebar in the AASHTO code

affected the development length for rebar in UHPC? 5 YES

We need a Special Provision / Specification for UHPC.

Are there some good examples that can be shared? 4 YES

Did NYSDOT receive any public complaints regarding the patchwork

appearance of the new bridge deck? 4 YES

Do the shear pockets and panel to panel connections wear differently?

Does this cause traffic / ride concerns with time? 4 YES

Are there any concerns with galvanic corrosion between stainless steel

reinforcing bars and the metallic fibers? 4 YES

Do contractors realize cost and time savings after they have completed

a few projects? 3 YES

How many link slabs have been completed in the State of New York?

What is the minimum link slab depth?

Are these standard practice for rehabilitation projects in NY?

2 YES

What does NYSDOT use for a ride surface?

Are the deck connections left exposed? 2 YES

How do you create the exposed aggregate finish on precast deck panels?

Does it really help bond? Is it really needed? 2 YES

Are barrier connections completed at the same time as deck connections?

If so, are there increased "overpours" to account for the air escaping? 2 YES

Since UHPC is highly flowable, how far apart can you pour the concrete

and still fill all the joint spaces? 2 YES

What types of QC/QA field testing are required or needed during placement? 2 YES

Can McDonagh speak more to the methods that ensure successful

construction? 1 YES

What embedment lengths are you expecting for prestressing stands? 1 YES

Have any states used non-proprietary UHPC in recent deployments?

Or; are commercial products always used? 1 YES

Have unit costs of UHPC decreased over the years since there have

been more projects in the US?

1

YES


Questions Likes

Passed to

Moderator

Why do we think this is new?

Didn't Egyptians add straw to mud in ancient times? 0 YES

For the mock-up pours, could a high w/c ratio cement create the same

pore pressures as UHPC, or; would you recommend UHPC only for

the mock-up?

0 YES

For exposed aggregate do you use a performance specification

or method (prescriptive) specification? 0 YES

Has cracking due to restrained shrinkage been observed with UHPC

connections? 0 YES

How does the micro-cracking in the UHPC affect the permeability

and corrosion resistance? 0 YES

Can the panel speak to previously used methods for top forming?

Is there any method other than wooden strips and drilling fasteners

into the deck?

0 YES

How do you enforce the water-tightness portion of the UHPC

specification?

0 NO

What is the minimum depth of link slab detail used in NYDOT? 0 NO

Will the PowerPoint presentations be available to attendees? 0 NO

What type of corrosion resistant reinforcement was used on the

Pulaski Bridge? 0 NO

How much longer can UHPC spans be the conventional deck spans? 0 NO

To Mathew Royce; Have you tried link slabs on PPCB bridges?

Have you ever replaced bearings and/or found it necessary

to take a closer look at foundation piles?

0 NO

What is the temperature of UHPC during hydration? 0 NO

When replacing the joints with link slabs, is there any concern

with induced thermal forces causing rotation in the foundations? 0 NO

Has any consideration been given to using a larger bar spacing

within the connection joint?

Have other spacings been used?

0 NO

Does NY require overlays on UHPC decks? 0 NO

ICRI has established concrete surface profile criteria.

This might be useful when specifying the panel-edge surface.

Sample chips can be used for visual Y/N.

0 NO

How much do span lengths increase with UHPC? 0 NO

Have there been any analytical efforts on the performance of

these bridge joints? 0 NO

What is the minimum tensile strength of the steel fibers used in

the UHPC mix for DOT projects? 0 NO

Documents

Interactive Panel Proceedings - Iowa State University...the Pulaski Skyway, a 3.5 mile-long viaduct that links Newark, NJ with Jersey City, NJ. Altogether, 118 spans and 1 million