Abstract: Individual square shaped modules used in an assembly for underground storage of storm water and other fluid storage needs. Modules are assembled into a resultant square tilling shape for maximized structural strength and material use efficiency. Internal square shaped modules are assembled and encased by external square shaped modules. Internal adjacent modules are in direct fluid communications with one another through a channel-less chamber. Internal square shaped modules drain into square shaped modules chamber where fluid is either stored or drained. Assemblies include various top and side pieces along with access ports for entry into said assembly.

Abstract: A storm water drain system and methods of assembling the same are provided. The system can be arranged to provide a water management function such as retention, detention, conveyance, or infiltration. The system can include a plurality of support modules positioned adjacent to one another to form a top deck, a bottom deck, and an interior space between the top deck and the bottom deck. The plurality of support modules can include a support module that has a bottom corbel extending from an outer surface of the support module. The bottom corbel can be located within the interior space and have a surface that contacts a portion of the bottom deck.

Abstract: Individual hexagonal shaped modules used in an assembly for underground storage of storm water and other fluid storage needs. Modules are assembled into a resultant honeycomb shape for maximized structural strength and material use efficiency. Adjacent modules are in direct fluid communications with one another via openings or windows in module side walls. Assemblies include various top and side pieces along with access ports for entry into said assembly.

Abstract: Systems and apparatuses protect subsurface conduit. Specifically, the systems and apparatuses protect subsurface conduit by disposing one or more rigid caps over a length of the subsurface conduit under a roadway for decreasing and/or eliminating impacts and/or damage to the subsurface conduit caused by automobiles and other vehicles utilizing the roadway. Methods of making and using the same are further provided.

Abstract: Modules for controlling a flow of water and methods of assembly of modules to establish indirect flow of water through a modular system. Modular systems for controlling a flow of water having beams extending across the modules to direct the flow of water in an indirect manner or a serpentine or semi-serpentine manner. Modular storage and controlled outflow systems for treatment and filtration of water.

Abstract: A system providing environmentally friendly pathway tunnel utilizes bridge units having a bottom configuration with multiple elongated beams and slots. One or more of the beams includes upstanding sedimentation members that are spaced apart along a span of the tunnel. The system interacts with the flowing water and earthen material in the flowing water such that capture and settling of the earthen material at locations along the tunnel occurs to produce a more natural water flow pathway along the tunnel.

Abstract: A box culvert assembly and method of forming a box culvert assembly is provided. The boxes forming the assembly comprise portions configured to allow pivoted assembly of one box into another, while reducing the likelihood of high stress or fracture. The box assembly further allows for a generally tight seal between the boxes.

Abstract: Modules for use in an assembly for managing the flow of water beneath a ground surface and assemblies of such modules are disclosed. The modules include supports and a deck portion and the supports are spaced apart and form channels with a main section of the deck portion. The deck portion also includes at least one section extending from a main section.

Abstract: A box culvert assembly and method of forming a box culvert assembly is provided. The boxes forming the assembly comprise portions configured to allow pivoted assembly of one box into another, while reducing the likelihood of high stress or fracture. The box assembly further allows for a generally tight seal between the boxes.

Abstract: This invention relates to a novel environmentally compatible culvert system. More particularly, this invention relates to a novel multi-component modular environmental culvert system which is constructed of reaction injection molded components, comprising modular interconnecting bases, modular interconnecting corrugated arch systems, and modular joining binders. A modular culvert system comprising: (a) at least one base grid module; (b) at least one corrugated arch module resting on the grid; and (c) an arch shaped binder module adjacent the arch module.

Abstract: A concrete culvert assembly includes a set of spaced apart elongated footers, a plurality of precast concrete culvert sections supported by the footers. Each concrete culvert section has an open bottom, an arch-shaped top wall and spaced apart side walls to define a passage thereunder, each of the side walls extending downward and outward from the top wall. Each of the side walls has a substantially planar inner surface and a substantially planar outer surface. First and second haunch sections each join one of the side walls to the top wall. Each side wall is tapered from top to bottom such that a thickness of each side wall decreases when moving from the top of each side wall to the bottom of each side wall. A bottom portion of each side wall has an exterior vertical flat extending upward from a horizontal bottom surface thereof.

Abstract: A concrete culvert assembly includes a set of spaced apart elongated footers, a plurality of precast concrete culvert sections supported by the footers. Each concrete culvert section has an open bottom, an arch-shaped top wall and spaced apart side walls to define a passage thereunder, each of the side walls extending downward and outward from the top wall. Each of the side walls has a substantially planar inner surface and a substantially planar outer surface. First and second haunch sections each join one of the side walls to the top wall. Each side wall is tapered from top to bottom such that a thickness of each side wall decreases when moving from the top of each side wall to the bottom of each side wall. A bottom portion of each side wall has an exterior vertical flat extending upward from a horizontal bottom surface thereof.

Abstract: The system employs a two piece gully assembly to implement an NFT system. The system has a square-U shaped base with a flat lid that can be fastened to the base. One of the advantages of the assembly is in shipping where the bases and lids can be easily nested for transport. When compared to prior art gullies, the shipping volume of the present assembly is effectively minimized. In fact, ten gullies of the present assembly can be shipped in the same volume as a single prior art gully.

Abstract: A concrete culvert assembly includes a set of spaced apart elongated footers, a plurality of precast concrete culvert sections supported by the footers. Each concrete culvert section has an open bottom, an arch-shaped top wall and spaced apart side walls to define a passage thereunder, each of the side walls extending downward and outward from the top wall. Each of the side walls has a substantially planar inner surface and a substantially planar outer surface. First and second haunch sections each join one of the side walls to the top wall. Each side wall is tapered from top to bottom such that a thickness of each side wall decreases when moving from the top of each side wall to the bottom of each side wall. A bottom portion of each side wall has an exterior vertical flat extending upward from a horizontal bottom surface thereof.

Abstract: A method of providing an environmentally appealing region for water flow along an surrounded pathway tunnel involves providing a plurality of four-sided concrete bridge units in abutting relationship to create a surrounded pathway tunnel, one end of the tunnel located upstream along a water path and an opposite end of the tunnel located downstream along the water path; allowing water to flow through the surrounded pathway tunnel during a rain or other flow event; and providing a multiplicity of the four-sided bridge units with a corresponding bottom wall structure that interacts with the flowing water and earthen material in the flowing water such that capture and settling of the earthen material at locations along the tunnel occurs to produce a more natural water flow pathway along the tunnel.

Abstract: A reinforced soil arch having an archway form, a combination of alternating and interacting layers of compacted mineral soil and geosynthetic reinforcement material placed over and adjacent to the archway form, and a plurality of shear resisting devices secured to the exterior surface of the archway form. The shear resisting devices cause the archway form and the combination of alternating layers of compacted mineral soil and geosynthetic reinforcement material to act as an integral unit when static or dynamic loads are placed on the reinforced soil arch. Methods for constructing a reinforced soil arch are provided.

Abstract: A box culvert assembly and method of forming a box culvert assembly is provided. The boxes forming the assembly comprise portions configured to allow pivoted assembly of one box into another, while reducing the likelihood of high stress or fracture. The box assembly further allows for a generally tight seal between the boxes.

Abstract: Modules for use in an assembly for managing the flow of water beneath a ground surface and assemblies of such modules are disclosed. The modules include supports and a deck portion and the supports are spaced apart and form channels with a main section of the deck portion. The deck portion also includes at least one section extending from a main section.

Abstract: A concrete building system includes a set of parallel spaced apart strip footers and one or more precast concrete sections supported by the footers in a predetermined alignment. Each precast concrete section has a top slab integrally connected to a pair of equally flared legs. Each leg depends from an end of the top slab at an effective flare angle to form a corner. The precast section includes haunch sections formed between the top slab and each leg resulting in a corner thickness greater than the uniform thickness of the angled leg to which it is integrally formed and the top member. The length of the effective span of each section varies between 60 and 90 percent of the distance between the bottom-of-leg span. The sections can be used to construct bridges, culverts, underground storage units, fluid detention units and dam structures.

Abstract: The invention provides modular units, associated component parts, and assemblies of the modular units and component parts, including filtration systems, that are useful for making and using underground water management systems.

Abstract: A skewed end assembly for connection to an arch culvert structure is provided. The assembly may generally include an arch-shaped inner skewed panel and a wedge member having a partially arch-shaped profile adapted for engagement with the inner skewed panel. The inner skewed panel may include a ledge that may include a plurality of threaded anchors. The wedge member may include a lip adapted for engagement with the ledge. The lip may include a plurality of apertures for receiving a plurality of threaded connectors adapted for threadable engagement with the corresponding threaded anchors in the ledge. Two assemblies, each comprising an inner skewed panel and a wedge member, are placed at opposed ends of an arch-shaped bridge or culvert structure to provide generally co-planar skewed ends to the structure such that it may be positioned at an angle in relation to a roadway such that the skewed ends are generally parallel to the roadway.

Abstract: A system for articulably bearing a prefabricated structural member on a foundation includes a first static hinge interposed between the base of the upright of the structural prefabricated member and the foundation, and an additional static hinge which is also arranged between the base of the upright and the foundation and has a rotation axis parallel and separated from that of the first static hinge.

Abstract: A precast steel reinforced concrete bridge unit has an arcuate top wall integrally connecting opposite side walls, and a series of precast reinforced concrete counterforts are releasably connected to the top wall of the bridge unit at laterally spaced intervals. The counterforts have vertical end surfaces spaced from an end surface of the bridge unit, and end portions of reinforcing bars project from the vertical end surfaces of the counterforts. An end surface of the bridge unit is located on a horizontal casting surface, and a reinforced concrete headwall is cast on the casting surface with the reinforcing bars depending from the counterforts embedded in the concrete forming the headwall. After curing, the concrete headwall and counterforts are removed as a unit from the bridge unit to facilitate handling and shipping of the bridge unit and headwall and counterfort unit.

Abstract: An easy clean culvert system being formed of concrete, wherein the culvert system includes a plurality of culvert sections, each section having a cover that is removably coupled to a base portion of the culvert section. The cover may be removed and replaced in order to access the culvert system for easy cleaning. The culvert sections are coupled together to form the entire culvert system.

Abstract: A process for the construction of a segment of an open-air work by prefabricated structural members of reinforcing concrete, includes the steps of arranging first and second prefabricated structural members (18, 19) including an upright portion (22) and at least a cover portion (26), and the phase of installing the two structural members (18, 19) by resting the free ends (20) of the respective upright portions (22) on respective foundation portions (12), in such a manner that the two structural members (18, 19) are arranged symmetrically opposed. Each structural member (18, 19) has a cavity in correspondence of the respective cover portion (26), the cavities of the two structural members (18, 19) constituting a continuous channel (34) in order to allow to form a beam superimposed to the two members (18, 19) and fastened to them, by executing a casting (36) in said continuous channel (34) during the work.

Abstract: Methods and modules for use in a modular assembly are disclosed for retaining or detaining storm water beneath a ground surface. A module comprises a substantially horizontally disposed deck portion and at least one substantially vertically disposed side portion extending therefrom. The deck portion and side portion have respective end edges, and the side portion has bottom edges. The side portion and the deck portion define a longitudinal channel which is open at least at an end of the module. The side portion has at least one opening therein and defines a lateral channel in the module. The longitudinal and lateral channels are in fluid communication with one another. Each channel has about the same cross section and extends upwardly from the bottom edges to allow relatively unconstrained flow in the longitudinal and lateral directions.

Abstract: Methods and modules for use in a modular assembly are disclosed for retaining or detaining storm water beneath a ground surface. A module comprises a substantially horizontally disposed deck portion and at least one substantially vertically disposed side portion extending therefrom. The deck portion and side portion have respective end edges, and the side portion has bottom edges. The side portion and the deck portion define a longitudinal channel which is open at least at an end of the module. The side portion has at least one opening therein and defines a lateral channel in the module. The longitudinal and lateral channels are in fluid communication with one another. Each channel has about the same cross section and extends upwardly from the bottom edges to allow relatively unconstrained flow in the longitudinal and lateral directions.

Abstract: A box culvert and gasket assembly is provided that enables fluid-tight bell-and spigot joints to be formed between abutting ends of box culverts. The joints according to the assembly of the present invention can remain fluid-tight up to at least 13 psi of water pressure. The gasket is preferably a one-piece, endless rubber gasket that is applied over the end of a spigot that is rectangular in end elevation. The corners of the rectangular spigot are rounded to enable the gasket to extend continuously over the corner without the need for 45° cuts and splices. Preferably, the gasket is made from a single elongate gasket piece that is cut to size and that has ends that are bonded together via a butt vulcanization technique. A storm drain and sewer assembly and a method of forming a fluid-tight bell-and spigot joint are also provided.

Abstract: Plastic liner sections define a drainage channel when placed end to end. Each end has a stiff, double walled flange at each side of the end adapted to butt up to a similar flange at the adjacent end of the next sections. The double walled construction of the flanges stiffens the ends significantly reducing the risk of deformation by the hydrostatic forces produced by wet concrete during installation. A groove is formed inwardly of the flanges on a female end of the liner section and receives a sealing ring, which is held in place by a lip formed on a male end.

Abstract: Disclosed is a fluid, namely stormwater, management system employing a chamber having an overall substantially constant curve cross-sectional geometry, with an a-semicircular constant curve cross-sectional geometry preferred. This chamber, which preferably follows both AASHTO standard specifications for Highway Bridges, Section 18, and Corrugated Polyethylene Pipe Association (CCPA) specifications, can further comprise corregations, support members and/or connecting elements to further add structural integrity.

Abstract: An arch shape cross section chamber for receiving and dispersing stormwater when buried beneath the surface of the earth is corrugated and has a cross section geometry which is a continuous curve. Preferably, the curve is a truncated semi-ellipse. A chamber also has a combination of a standard corrugations along most of the length, in combination with smaller end corrugation with standard corrugations, to enable joining of chambers in overlap fashion, as a string; corrugations which have elliptically curved corrugation widths when viewed from the side of the chamber; and, sidewall base flanges which have turned up outer edges in combination with fins which connect said edges with the curved chamber sidewall. A domed end cap is adapted to both close the end of the chamber and to be positioned within the chamber length to provide a baffle.

Abstract: Methods and modules for use in a modular assembly are disclosed for retaining or detaining storm water beneath a ground surface. A module comprises a substantially horizontally disposed deck portion and at least one substantially vertically disposed side portion extending therefrom. The deck portion and side portion have respective end edges, and the side portion has bottom edges. The side portion and the deck portion define a longitudinal channel which is open at least at an end of the module. The side portion has at least one opening therein and defines a lateral channel in the module. The longitudinal and lateral channels are in fluid communication with one another. Each channel has about the same cross section and extends upwardly from the bottom edges to allow relatively unconstrained flow in the longitudinal and lateral directions.

Abstract: This invention relates to a novel design of reinforced soil arch which can be used to construct bridges, overpasses, snowsheds, landslide or rock fall protection structures, and the like. More particularly, this invention pertains to an innovative use of mineral soil (clay, silt, sand, gravel, cobbles, boulders, broken rock or mixtures of any or all of the foregoing) to construct a reinforced soil arch that can be used for numerous purposes. A method of constructing a reinforced soil arch comprising constructing an arch utilizing a combination of layers of compacted mineral soil and reinforcement in a manner that supports both the dead load of the structure and a live load imposed on the structure.

Abstract: This invention relates to a novel design of reinforced soil arch which can be used to construct bridges, overpasses, snowsheds, landslide or rock fall protection structures, and the like. More particularly, this invention pertains to an innovative use of mineral soil (clay, silt, sand, gravel, cobbles, boulders, broken rock or mixtures of any or all of the foregoing) to construct a reinforced soil arch that can be used for numerous purposes. A method of constructing a reinforced soil arch comprising constructing an arch utilizing a combination of layers of compacted mineral soil and reinforcement in a manner that supports both the dead load of the structure and a live load imposed on the structure.

Abstract: A precast safety end for use with culverts on highway, driveway, and road drainage crossings has a base having a depending flange at its outer end and an upright wall at its inner end, and opening in the wall to register with the opening in an abutting pipe culvert. Upright wings on each side of the base connect with the upright end wall. The side walls taper downwardly from the upright end wall to the end of the base. The side walls have outwardly protruding wings on either side to prevent erosion and overgrowth of grass.

Abstract: A method of load reduction on buried culvert using an EPS block is disclosed. A culvert foundation is constructed at a place where a culvert will be buried, and the culvert is put on the foundation, and then, both sides of the culvert are banked with filling earth. EPS blocks are paved in multiple layers on the top surface of the culvert, or geosynthetics and an ESP block are paved on the culvert, and then, filling earth is banked on the geosynthetics or the ESP block and a final ground level is compacted. As a result, compression occurs from the EPS block, deformation of the inside earth is caused artificially, and arching is generated. Accordingly, the method has vertical earth pressure reduction effect, thereby preventing an increase in the section of the culvert due to overburden of the banked earth and an increase in vertical load due to a settlement amount of the culvert buried on the weak ground and a relative settlement difference of surrounding earth, and improving durability of the buried culvert.

Abstract: A deep corrugated structural metal plate having a cold roll formed, uniform uninterrupted short radius of curvature along at least a portion of the plate's length in the range of about 450 mm up to about 3100 mm.

Abstract: A composite concrete reinforced corrugated metal arch-type structure comprises: i) a first set of shaped corrugated metal plates interconnected in a manner to define a base arch structure with the corrugations extending transversely of the longitudinal length of the arch; ii) a second series of shaped corrugated metal plates interconnected in a manner to overlay the first set of interconnected plates of the base arch, the second series of plates having at least one corrugation extending transversely of the longitudinal length of the arch with the troughs of the corrugation of the second series of plates secured to the crests of the first set of plates; iii) the interconnected series of second plates and the first set of plates define individual, transversely extending, enclosed continuous cavity filled with concrete to define an interface of the concrete enclosed by the metal interior surfaces of the second series of crests and first set of troughs; iv) the interior surfaces of the cavity for each of the

Abstract: A floating link archway system which is useful for building access roads, such as logging roads and secondary roads in wilderness areas that include waterways such as streams and creeks, without causing significant adverse impact to sensitive environment. The archway system is constructed of a plurality of modules having a semi-cylindrical configuration with flanges at each end, an integral semicircular upstanding reinforcing rib between the flanges, footing contact areas at the base of each side of the semi-cylindrical body, and protective caps which cover the entirety of adjacent flanges of pairs of adjacent modules and thus enable the modules to move independently of one another.

Abstract: A composite concrete reinforced corrugated metal arch-type structure comprises:

Abstract: A plastic apron endwall is connected to a drain which extends under a highway. The apron endwall is in the form of an upwardly opening trough having a general wedge shape and incorporates lateral wings which extend outwardly from the sides of the apron end wall into the surrounding soil, so that as installed, the soil overburden prevents the apron end wall from being displaced upwardly by buoyancy forces in the event that the ditch into which the apron end wall drains becomes flooded. The total planar area of the wings is selected so that the overburden, that is the soil which lies above the wings, is sufficient to offset any buoyancy force produced by water saturated the soil in which the apron end wall is embedded.

Abstract: A bi-partite sluiceway apparatus with silt removal tray components consisting of a pair of elongated three-sided bottom containment trays with triangularly shaped soffet units affixed to outer walling of lateral sides of each and with each having oppositely inclined beveled posterior ends with each tray holding at top edging of lateral sides thereof, elongated three-sided silt collection trays each with beveled posterior ends as well and with each silt collection tray having a grasping plate characterized by the presence of a concentrically positioned through hole and being affixed to lateral sides thereof near a front end thereof and with each silt collection tray being swiveably lockable to a containment tray by way of a nut and bolt assembly insertable through concentric through holes near frontal ends of each tray, and with all beveled ends in contact with one another upon complete assembly of the apparatus within a roadbed.

Abstract: A joint for pre-cast concrete twin-leaf arch sections is self-aligning when the two arch sections are initially brought into abutting contact with each other. The joint provides a rigid connection between the twin units and is achieved on site by means of re-inforced cast-in-place concrete. Reinforcement splices for the connection are lap splices, and the joint allows pouring the cast-in-place concrete without the need of formwork. For load distributing purposes, a continuous connection of individual arch rings in the longitudinal direction at the arch crown is possible. An initial abutting contact between the twin units is provided by the joint of the present invention. The contact provided by the joint of the present invention is self-aligning, locking, allows the controlled transmission of the abutting force and allows for a temporary connection. The joint includes mechanical elements for aligning and locking the two arch sections together.

Abstract: Method of construction of a vault, in which at least two half-shells (1-8; 60) are brought to bear against one another by means of at least two bearing pieces (30, 50; 70) which are mated and, each half-shell (1-8; 60) comprising an upper edge (21; 61) and a bottom lip (22); each bearing piece (30, 50; 70) is fixed removably to a half-shell (1-8; 60), the two half-shells (1-8; 60) are brought to bear against one another temporarily via their bearing piece (30, 50; 70) without their bottom lips (22) being brought to bear against one another, a keystone-forming material is cast between said upper edges (21; 61), on the bottom (14) constituted by the lips (22), so as to bring about continuous transverse joining together of the half-shells (1-8; 60), and then the bearing pieces (30, 50; 70) are removed so as to effect load transfer from the bearing pieces (30, 50; 70) to the half-shells (1-8; 60). The invention is suitable for the construction of a passage under an embankment.

Abstract: A civil engineering structure having an arched wall including a plurality of curve shaped elements. Each element bears against one or more other similar elements and has a recess arranged in an outer face for casting a concrete assembly capping piece and reinforcements. Each element also includes at least one rigid bearing piece fastened to the element and has, at a free end of the rigid bearing piece, a surface with a non-planar profile. The rigid bearing piece comes to bear against a similar piece of another element located opposite it. The two rigid bearing pieces have complementary profiles making it possible for them to be wedged vertically.

Abstract: A prefabricated structure for the construction of open air structures, particularly motorway flyovers, underpasses, bridges, tunnels, underground carparks and the like, includes a plurality of prefabricated elements of reinforced concrete. These elements are able to define the side walls and the deck of the work with adjacent longitudinal sections of the structure which rest on a foundation at the base of the work. Each section of the structure includes a pair of side elements which rest on the foundation via a static hinge and are intended to be disposed symmetrically with respect to the axle of the structure so as to assume a substantially L-shaped configuration. A substantially rectilinear prefabricated element is interposed centrally between two side elements and is anchored thereto so as to define a central portion of the deck of the work.

Abstract: A prefabricated pre-cast culvert including a box-shaped culvert body, which is open at both longitudinal ends thereof to have opposite end surfaces, a pair of mortar grooves each formed on an associated one of the end surfaces in such a fashion that it extends along the entire length of the associated end surface, and a plurality of couplings arranged in each of the mortar grooves. Each coupling includes a pair of connecting eye bolts threadedly coupled to the culvert body. Each coupling has an eye which is aligned with an eye of a corresponding coupling provided at another culvert to be longitudinally connected to the culvert when the culverts are in contact with each other at facing end surfaces thereof. The culverts are connected to each other by a steel rod inserted into the aligned eyes along the mortar groove.

Abstract: A method for controlling deformation of an erected structural metal plate culvert or underpass during backfilling of the erected structure comprises: building progressively a reinforced earth retaining system on each side of the erected structure by alternately layering a plurality of compacted layers of earth with interposed layers of reinforcement to form reinforced earth on each side of the erected structure and securing to each side of the structure each said layer of reinforcement in the reinforced earth, whereby such securement of each said layer of reinforcement to said structure controls deformation of the erected structure during backfilling with the reinforced earth on each side of the structure. The layer of reinforcement may be a plurality of strips extending away from the structure, or a reinforcement mat of interconnected rods.

Abstract: A cylindrical structure suitable for use as a drainage culvert made from the side walls of discarded motor vehicle tire casings. The side wall sections are stacked and bonded in axial alignment so that the concave face of each of the next adjacent side wall faces the convex face of the next adjacent side wall. One end face of the structure is thus concave and the other end face is convex so that the cylindrical structure can be placed in close alignment with the concave end face of one cylinder in close abutting contact with the convex end face of a second cylinder. Wide kerfs are cut in selected side walls between the outer rim of the side wall and the inner rim so that the selected side walls can expand or contract during banding to provide a rather uniform opening in the cylinder. The kerf also allow the cylinders to weep when water is being conducted therethrough.

Abstract: A composite concrete reinforced corrugated metal arch-type structure comprises a first set of shaped corrugated metal plates interconnected in a manner to define a base arch structure with the corrugations extending transversely of the longitudinal length of the arch and a second series of shaped corrugated metal plates interconnected in a manner to overlay the first set of interconnected plates of the base arch, the second series of plates having at least one corrugation extending transversely of the longitudinal length of the arch with the troughs of the corrugations of the second series of plates secured to the crests of the first set of plates. The interconnected series of second plates and the first set of plates define individual, transversely extending, enclosed continuous cavities filled with concrete to define an interface of the concrete enclosed by the metal interior surfaces of the second series of crests and first set of troughs.