Inventor 1 : Su Hao

Inventor 2: Alexander J. Hao

43 Bower Tree, Irvine

CA 92603 U. S. A.

Date: March 4 ^th , 2019

Related Art : US9,222,260B1

Interested government agencies: US Departments of Transportation; Transportation Research

Board (TRB) , US States’ DOTs.

Citations:

Other References

[1] MANUAL FOR DESIGN, CONSTRUCTION, AND MAINTENANCE OF ORTHOTROPIC

STEEL DECK BRIDGES, FHWA, US DOT, 2012

[2a] Eurocode 3 (2005). Design of Steel Structures - Part 1-9: Fatigue, EN 1993-1-9

[2b] Eurocode 3 (2010). Design of Steel Structures - Part 2: Steel Bridges, EN 1993-2

[3a] Japanese Road Association (2002). (JSBF: Japanese Steel Bridge

Fatigue Design Guideline )

[3b] Japanese Road Association (2012). (JBDC: Japanese Bridge Design Code)

[3c] Japanese Society of Steel Construction (2012). (JSSF: Japanese

Steel Structure Fatigue Design Guideline)

[4] Su Hao, Closure to“135W Bridge Collapse ^" ’ by S. Hao, ASCE J. of Bridge Engineering, V.18(9),

2013, pp.929-930.

[5] Su Hao, Structural Fatigue Damage Evaluation in Bridges and Orthotropic Decks, 3RD

ORTHOTROPIC BRIDGE CONFERENCE PROCEEDINGS, June 26-28, 2013, Sacramento,

California.

9 figures, 13 claims

Field of Invention

Composite sheet matrixes to protect weight-carrying platform’s surfaces, such as bridges’ decks, ships’ decks, and seashore oil-drill platform’s surface, particularly, the steel decks of orthotropic bridges

Background of the invention

Taking bridge’s deck as example: more than 80% of super-long spanned steel bridges in the world are made of orthotropic span-beam that is a steel beam-box with trapezoid cross section with welded U-shaped ribs inside beam-box along the longitudinal direction of the beam, see Fig. 1(a). An orthotropic bridge’s steel plate-deck, reinforced by welded U-ribs, provides sufficient sectional modulus of bending for the structure to carry bridge’s weight itself (dead load) while directly takes the live load’s weight above, e.g. vehicles, which has been considered as an innovative structure in last century and been applied in many major bridges in US, for examples, the Golden Bridge and Bay Bridge in San Francisco, the New Tacoma-Narrow Bridge in

Washington State, and many other long-span steel bridges in eastern coast. For this kind of bridges that were built 20 years ago or older, the thicknesses of their orthotropic decks were generally designed less or equal 12mm. However, recently, at least 14 mm of thickness is mandated in the new orthotropic bridges’ design specifications in US[1], Europa[2], and Japan

[3] The reason of this change is because severe damages, in the form of fatigue cracking, have been observed in many aged orthotropic steel bridges’ decks around world, see the examples in

Fig. 1(c). Engineers have identified that the traditional pavement materials, which work well for other kinds of bridges’ decks, have limited function to protect orthotropic steel decks. Because such a deck is a part of a bridge’s beam-span, it is generally impossible to remove a damaged part if not replacing entire span. To assist solving this engineering problem, the present invention provides a class of composite sheet that is block of composite pavement matrix, termed“CPM” thereof, which can be either used as a new pavement matrix to repair and recover an aged orthotropic bridge’s steel deck, or to be manufactured associated with a new bridge’s steel beam’s deck to reduce the structural weight, by which CPM can be used directly to expose to the forces of carried weights or is covered by thinner traditional pavement, e.g. asphalt, for better comfortableness to the drivers in vehicles passed over.

Generally speaking, the structural function of a weight-carrying structure’s platform, such as a bridge’s deck or a building’s floor, is to transfer the weight-induced force-flow caused by carried stuffs above, such as vehicles, humans, goods and facilities, through the structure’s frame to its foundation. The stresses experienced by each material element on such a platform’s surface can be categorized into two classes: (A) the stresses caused by directly imposed contact forces, which introduces localized stress concentration while causes surface wearing; the contact forces also include two kinds: gravity and additional dynamic force, for example, weight of a carried vehicle and additional dynamic forces when it breaks, see Fig. 1(d) [4,5]; (B) stresses due to global force-flows, for example: bending moments-induced tension or compression, see Fig. 1(d).

By the conventional design for this kind of platforms in last century, more attentions had been given to the class (B) stresses to assure global structural integrity. Wearing and the effects of class (A) stresses to material’s damages often emerges only after long-term services, which becomes a general safety issue of maintenance for a structure like a bridge that is supposed to last 75 or 100 years. The disclosed invention can also be applied to other platforms with the similar issues. The materials’ damages, such as fatigue cracks, generally occur around the areas with material’s heterogeneities, such as welded joints, and the local area with sudden geometric changes. The latter introduces localized stress concentration; and the former reduces material’s strength that promotes damage’s initiation in the form of micro-cracking under applied stresses.

The locations in a structure with these kinds of feathers are termed“hot spot” in bridge engineering community. The initiation and growth of materials’ damages in a hot spot are generally driven by the both of directly-imposed contact/impact forces and the global force flow- induced stresses, i.e. a combination of the stresses of aforementioned class (A) and class (B).

Summary of the invention

This invention discloses a class of Composite Pavement Matrixes to protect weight- carrying structure’s platform, which is termed“CPM” thereof. CPM is contains periodically- arranged cavities that are separated by multiple pieces of plates, see Figs. 2-5. The geometries and sizes of the cavities and the plates are designed to satisfy the conditions defined in the previous section. A piece of CPM can be either made as a part of a said weight-carrying structure or is a pre-fabricated sheet that can be paved onto a surface of a said weight-carrying structure’s platform.

A application of CPM is to protect a weight-carrying platform’s surface, so it is designed to satisfy the following conditions:

(0 Sufficient local protection: be able to smear out a concentrated force imposed on its surface into a large area of the platform’s surface covered beneath. (ii) Robustness: be strong enough to sustain imposed concentration force and impacts for long time.

(iii) Strengthening global structure: be able to reinforce the strength and stiffness of the platform protected.

(iv) Fitness: be able to fixed onto protected platform’s surface without additional risk to promote extra secondary damages.

(v) Durability: be able to last long under minimized maintenance efforts.

(vi) Economy: easily for manufacturing, affordable for applicants

An additional explanation for the requirement (iii): both the class (A) and class (B) stresses in Fig. 1 may promote localized material damages; when the condition (i) is satisfied to protect the effect of class A stresses, damage may still keep growing under class (B) stresses.

Capability to strengthening a platform means not only protecting its surface but also sharing global force-flows to reduce the effects of class (B) stresses.

Additional explanation for the requirement (iv): by the methods to attach a protective sheet onto a steel deck, such as welding or to drill hole for bolted-in, may cause additional material heterogeneity and localized high stress, to create additional above-mentioned“hot spot” that may trigger the secondary-damages. Therefore, the ideas how to keep welding or hole- drilling, when this kind of methods has to be applied, away from a deck’s hot spot-like locations is a part of this invention, which is crucial for practical applications [4,5] Therefore, the basic embodiments of CPM include: (I) structural blocks that in the forms of a piece of plate and a block of material with designed geometries for specified structural functions; (II) the structural blocks configurate a matrix that contains plurals of cavities with designed geometries for specified structural functions; (III) the materials to fill into the cavities for specified structural functions; (TV) the methods to fix a block of CPM onto a weight-carrying platform’s surface; wherein the underlying mechanisms of the embodiments (I, II, III) are to assure the satisfactions of the conditions i, ii, iii, iv, vi, and vii; wherein the underlying mechanisms of embodiment (IV) are for the satisfaction of the condition v.

According to design details of the embodiments, invented CPM composites include three types, termed Type-I, Type-II, and Type-III Composite Pavement Matrixes and abbreviated respectively as CPM-I, CPM-II, and CPM-III thereof.

Fig. 2 is schematic view of a Type-la CPM, a member that belongs to a subgroup of

CPM-I and termed“CPM-Ia” thereof. A CPM-Ia is attached onto an orthotropic steel bridge’s deck, which comprises a top plate, a bottom plate, and plurals of plate-strips configurated in periodic wavy geometry and formed the arch-shaped plate-grid; wherein the surfaces of each plate-strip is perpendicular to the surface of a weight-carrying platform.

Fig. 3 is schematic view of a Type-lb CPM, a member that belongs to another subgroup of CPM-I and termed“CPM-Ib” thereof, which is a block of CPM-Ia matrix but with additional material filled into the cavities left in the matrix.

A composite sheet of CPM-Ia or CPM-Ib that does not have top plate defines another subgroup of CPM-I, termed CPM-Ic thereof. A composite sheet of CPM-Ia or CPM-Ib that does not have bottom plate defines another subgroup of CPM-I, termed CPM-Id thereof. A composite sheet of CPM-Ia or CPM-Ib that does not have bottom plate and top plate defines another subgroup of CPM-I, termed CPM-Ie thereof.

Fig. 4 is schematic view of a Type-IIa CPM, a subgroup of CPM-II and termed“CPM-IIa” thereof. A composite sheet of CPM-IIa comprises a top plate, a bottom plate, and an arch-framed wavy-plate in-between; wherein said arch-framed wavy-plate has a periodically-distributed, specially-designed, geometric pattern to better sustain load imposed above; wherein said arch- framed wavy-plate comprises a part of upper arch geometry with its top touched onto said top plate, a part of lower arch geometry with its bottom touched onto said bottom plate, and transition parts in-between; wherein said bottom plate is bolted onto the orthotropic bridge’s deck; wherein the holes drilled for bolting on the bridge’s deck are arranged at the locations without the risk to introduce a secondary fatigue“hot spot” based on the analysis in [4,5] and illustrated in Fig. 1(e).

Fig. 5 is schematic view of Type-IIb CPM, another subgroup of CPM-II and termed

“CPM-IIb” thereof, which has the same structural frame as the CPM-IIa matrix but with additional material filled into the cavities that are either confined by the wavy plate and the top plate, termed upper cavities, or that confined by the wavy plate and the bottom plate, termed lower cavities, or both of them. When the top plate is made of the material that is the same as the filling material in the upper cavities, this defines another subgroup of CPM-II and termed“CPM-IIc” thereof.

Fig. 6 is schematic view of a Type-IId CPM, another subgroup of CPM-II and termed

“CPM-IId” thereof, which is a block of CPM-IIa matrix but comprises at least one of the following two groups of supporting blocks: the group of upper-support blocks that are inserted into the upper cavities without proximity to adjacent top plate and arch-framed wavy-plate; and the group of lower-support blocks that are insert into lower cavities without proximity to adjacent bottom plate and arch-framed wavy-plate.

When a composite sheet of CPM-IId with at least one cavity is filled by another filling material, it defines another subgroup of CPM-I1 and termed“CPM-IIe” thereof; wherein said cavity is either a subspace of one upper cavity confined by inserted upper-supporting blocks or a subspace of one lower cavity confined by inserted lower-supporting blocks.

When the top plate of a CPM-IId or CPM-IIe is made of the material that is the same as the filling material in upper cavities, this defines another subgroup of CPM-II and termed“CPM- nf’ thereof.

When a composite matrix of any subgroup of CPM-IIa to CPM-IIe is without the top plate in Figs. 5 and 6, this defines another subgroup of CPM-II and termed“CPM-IIg” thereof.

When a composite matrix of any subgroup of CPM-IIa to CPM-IIf is without the bottom plate in Figs. 5 and 6, this defines another subgroup of CPM-II and termed“CPM-IIh” thereof.

When the arch-framed wavy-plate in a composite sheet, which belongs to any of CPM- n’s subgroups, has a flat top part parallel to adjacent top plate, or has a flat bottom part parallel to adjacent bottom plate, or has the both, see Figs. 7 and 8, this defines a subgroup of the Type-

III CPM, i.e. CPM-m. Any of subgroups of CPM-II has its counterpart subgroup in CPM-m; the two counterpart subgroups are exactly the same but the arch-framed wavy-plate in any one of the

CPM-m subgroups has at least one flat-part parallel to the weight-carry platform’s surface .

Fig. 9 introduces the methods to fasten CPM onto weight-carry platform’s surface by bolting, so as to avoid the creation of secondary fatigue hot spot; (a) directly through the flat segment’s margin part of arch-shaped wavy-plate; (b) through the bottom plate’s extra extension legs; (c) directly through the flat segment’s extra extension legs of arch-shaped wavy-plate; (d) through the bottom plate’s extension part

Brief Description of the Drawings

Fig. 1 (a) An orthotropic bridge is under construction [1]; (b) a finite element model for a orthotropic bridge that gives the results in (d) and (e) of this figure; (c) fatigue cracks detected in other aged bridges; (d) live loads caused class-A stresses contours; (e) live plus dead loadsinduced Class-B stresses contours.

Fig. 2 Schematic diagrams of the embodiment for CPM-Ia, a subgroup of Type-I of Composite

Pavement Matrixes (CPM).

Fig. 3 A schematic diagram of the embodiment for CPM-Ib, a subgroup of Type-I of Composite

Pavement Matrixes (CPM).

Fig. 4 A schematic diagram of the embodiment for a Type-Da CPM, a subgroup of Type-D

Composite Pavement Matrixes (CPM).

Fig. 5 Schematic diagrams of the embodiment for a Type-Db CPM, another subgroup of Type-D

Composite Pavement Matrixes (CPM) - (a) filling material filled in both upper and lower cavities; (b) filling material filled in upper cavities; (b) filling material filled in lower cavities

Fig. 6 A schematic diagram of the embodiment for a Type-Dd CPM, another subgroup of Type-

D Composite Pavement Matrixes (CPM).

Fig. 7 Schematic diagrams of the embodiments for a Type-Dig CPM, (a) a CPM-DIg that is with bottom plate and filled by a pavement filling material in upper cavities and covering the composite sheet; (b) a CPM-DIg that is without bottom plate but with a pavement filling materials that is filled into upper cavities and covers the composite sheet

Fig. 8 A schematic diagram of the embodiment for a Type-DId CPM, another subgroup of Type-

ID Composite Pavement Matrixes (CPM). Fig. 9 Schematic diagrams of the embodiments to fasten a CPM sheet onto a weight-carrying platform’s surface at the latter’s margin area that will not create the secondary fatigue hot spot;

(a) using bolts to fasten a Type-IIIg sheet directly onto the platform’s deck at the parts of flat segments of arch-framed wavy-plate; (b) using bolts to fasten Type-IIIg at its bottom plate’s extension legs to the platform’s deck, so as to avoid the area that may create secondary fatigue hot spot; (c) using bolts to fasten a Type-IHg sheet directly onto the platform’s deck through the extension legs of arch-framed wavy-plate’ s flat segment; (d) using bolts to fasten Type-IIIg at its bottom plate’s extension part to the platform’s deck, so as to avoid the area that may create secondary fatigue hot spot.