Modular Precast Concrete Assembly with Sleeve Grout Connection
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Solution Overview
Problem
Conventional methods for constructing elevator shafts and stairwells are time-consuming and expensive, requiring heavy labor and extensive scaffolding, which negatively impacts building schedules and makes it difficult to meet project deadlines.
Innovation Solution
The use of modular precast concrete structures with integrated rebar members and a sleeve system for alignment and grouting, along with a method of erecting these structures without scaffolding by aligning and connecting precast segments using rebar dowels and grout, forming a 2-hour fire-rated assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional CMU construction methods are used for elevator shafts and stairwells, then structural strength and fire rating requirements are met, but construction time and labor costs increase significantly
Solution Approach 1:
The elevator shaft and stairwell structures are divided into modular precast concrete segments that can be manufactured off-site and assembled quickly on-site. Each segment is pre-reinforced with rebar and pre-grouted, eliminating the need for repetitive on-site construction operations while maintaining structural integrity through standardized connection details.
Solution Approach 2:
Reinforcement bars, grout, and fire-rated materials are installed in the precast segments before they leave the manufacturing facility. This preliminary action ensures that structural strength and fire rating requirements are met while eliminating time-consuming on-site operations for rebar placement, grouting, and fireproofing.
2Ease of operation
If conventional construction methods with scaffolding are used, then worker access to full height structures is provided, but safety hazards and labor costs increase
Solution Approach 1:
The structure is built in manageable modular segments that can be handled and positioned without requiring full-height scaffolding. Each segment is self-contained with all necessary reinforcements and fire-rated assemblies pre-installed, allowing workers to perform tasks at ground level during manufacturing and minimize time at heights during assembly.
Solution Approach 2:
The precast segments are designed to be self-sufficient with all reinforcements, grout, and fire-rated materials integrated during manufacturing. This eliminates the need for workers to perform hazardous on-site operations at height, as the segments arrive ready for simple mechanical connection and alignment.
3Productivity
If modular precast concrete structures are used, then construction time and labor costs are reduced, but connection complexity between segments increases
Solution Approach 1:
The connection system is itself segmented into standardized, repeatable components that simplify the assembly process. Each segment uses identical connection details with aligned rebar, standardized grout pockets, and consistent alignment features, reducing the complexity of connections as the number of segments increases.
Solution Approach 2:
All segment connections use the same homogeneous connection methodology with consistent grout formulations, reinforcement placement patterns, and alignment procedures. This uniformity reduces the learning curve for workers and simplifies quality control, offsetting the initial complexity of the precast connection system.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach significantly reduces erection time, eliminates the need for scaffolding, and minimizes labor costs, allowing for faster project completion and improved safety by reducing the duration and hazards associated with working at heights.
Implementation Method 1
a grout positioned within the sleeve
Implementation Method 2
a seal positioned between the first precast concrete structure and the second precast concrete structure; forming a 2-hour fire-rated assembly
Implementation Method 3
The rebar dowel extends through the aperture in the sleeve and is at least partially received within the sleeve. The second rebar member is aligned with the first rebar member along an axis.
Data Source
AI summary
An assembly comprising a first precast concrete structure including a first rebar member and a second precast concrete structure including a second rebar member. The second rebar member is aligned with the first rebar member along an axis. The assembly further includes a sleeve with an aperture. The sleeve is coupled to the first rebar member. The assembly further includes a connecting member coupled to the second rebar member, and a rebar dowel coupled to the connecting member; wherein the rebar dowel extends through the aperture in the sleeve and is at least partially received within the sleeve. The assembly further includes a grout positioned within the sleeve; a gasket positioned between the sleeve and the connecting member; a seal positioned between the first precast concrete structure and the second precast concrete structure; and a shim positioned between the first precast concrete structure and the second precast concrete structure.